Got questions about growing vegetables and fruit in Maine?

Extension experts identifies a plant sample for a client; photo by Edwin Remsberg

Ask the UMaine Extension gardening experts!

With years of experience in home horticulture and commercial agriculture, our experts help beginning gardeners achieve successful harvests, encourage gardeners and commercial farmers to donate excess produce to those in need, and use gardening as a vehicle to develop communities.

If you have a question about growing vegetables and fruit in Maine, you are welcome to


Q&A 2017

Answers to this season’s gardening questions are provided by Donna Coffin, Extension Educator, UMaine Extension Piscataquis & Penobscot Counties; Caragh Fitzgerald, Associate Extension Professor, Agriculture, UMaine Extension Kennebec County; Kate Garland, Horticultural Professional, UMaine Extension Penobscot County; Marjorie Peronto, Extension Educator, UMaine Extension Hancock & Washington Counties; and Frank Wertheim, Extension Educator, Agriculture/Horticulture, UMaine Extension York County.

Q: Is there a product available to eliminate (or control) cattails, that doesn’t contain glyphosate? I am looking for a more ecofriendly alternative for our neighborhood to use in a common pond which supplies our fire hydrant, and is overrun with cattails. In researching this, everything I’m seeing online is essentially Roundup. I would appreciate hearing about any possible alternatives.

A: All aquatic herbicides pose a potential risk to non-target organisms, including other users of the water (swimmers, livestock, wildlife, etc.).  There are non-chemical methods for cattail control that you may want to consider.  Cornell University has a good review of these options in their Controlling Cattails publication.  Please note that the section about aquatic herbicides is NOT appropriate to Maine.  More information on the use of aquatic herbicides in Maine can be found on the Maine Department of Agriculture, Conservation, and Forestry’s website.

camp gardenQ: We are thinking of having our camp jacked up after we leave for the season. My question is whether I should: 1) move the plants I want to save that are around the camp a month in advance so I can water them and get them established for the winter, then move them back in the spring; or 2) have the plants moved for the 3-4 weeks in late October or November when the camp is jacked, then immediately placed back around the camp for the winter. We will not be here for this process, so the plants would not be watered during the 3-4 week interim period or upon their return to their permanent home. Which is the better option?

A: Given the time of year (mid-October), I would suggest moving the plants to a temporary location for the winter and replanting them in the spring. Since it has been fairly dry this fall, water them well before moving them and keep them watered at least through the end of the month. Once the ground freezes, mulch the plants with leaves, straw, evergreen boughs, or other such material to keep the plants from heaving out of the ground in the late winter/early spring. The plants will not have time to establish a good root system before the cold weather sets in.

Q: I have three huge copper beech trees in front of my home. Because the ground under them receives little sun, I had been encouraging a moss lawn. Last year I was unable to weed the area and now it is covered with weeds with some moss and a bit of grass. I have been told that I cannot use any type of weed killer under these trees and I do not know what to do.

A: Your choice to encourage a moss lawn is a good one for a shaded area, such as under your beech trees. Could you take some high-resolution digital photographs of the weeds and grasses that are growing under the trees now? The photos should show the plants at a distance, closer up, a clear view of some single leaves, a clear view of how the leaf/leaves attach to the stem, and the flowers (if they are in flower). Email the photos to your local UMaine Extension county office for identification and advice.

Q: What is the best way to store a Crocosmia Lucifer for winter? Should I keep the corms in dirt or can I just keep them in a cool dark place for winter? I have not been successful in wintering this plant in the ground.

A: After curing in a well-ventilated area at 60° – 70° F for two to three weeks, Crocosmia can be stored in labeled paper bags at 35° – 40° F. The University of Minnesota’s Storing Tender Bulbs and Bulb-like Structures can give you additional details for these and other bulbs, corms, and the like.

Q: Are garden mums in Maine considered perennials?

A: Many chrysanthemums (such as most of those you will find for sale now) are not winter-hardy in our climate. If you are interested in a perennial chrysanthemum, you will need to look for one that specifically states that it is hardy to your winter hardiness zone. The University of Minnesota Extension’s Garden Chrysanthemums publication can also give you specific variety suggestions.

Q: Could you please help me identify these eggs that appear on my asparagus fronds? Typically I remove the stems on which they appear, but I’m curious to know what they are in the event it could be something beneficial.

A: Insect eggs are very difficult to identify. We suspect that these are Lepidopteran eggs, likely moth eggs, but cannot be certain. Apparently moths will lay eggs in some very unlikely places.

Q: Can anyone identify what these things are that are falling from trees in the back of my apartment building? They are hard shelled and disintegrate pretty quickly.

A: Those certainly look interesting! If you find any more of these, can you take some high-resolution pictures of the exterior and interior? It’s helpful if you can use a ruler for scale. You can also bring a sample to your local county Extension office: https://extension.umaine.edu/county-offices/. If you don’t find any more, this may remain a mystery.

Q: I have a residential raspberry plot which is especially heavy with fruit this fall. I am shaded by a neighbor as October advances and I am wondering about the use of outdoor grow lights to enhance fruit ripening and final yield. I don’t want to make the expense and effort to find out that it’s ineffective.

A: That’s an interesting idea, and one that can be attractive when there’s still fruit on the bushes. However, I don’t think that supplemental lighting will make a big difference in your crop at this time of year. The ripening of the raspberries will depend not only on light, as you mention, but also on temperature and the plant’s physiological stage. I don’t know what part of the state you’re in, but in Kennebec County, our daytime temperatures are going to be in the 60s for the next few weeks, with night time lows in the low to mid-40s. This will really slow down plant metabolism. By this time of year most bramble leaves are starting to show some discoloration — a sign of the typical end-of-season decline. Once that happens, the plant isn’t able to photosynthesize very well anyway, even if there is extra light.

Q: I started a few lowbush blueberry plants from seed from Maine. I am torn between leaving them outdoors, leaving them outdoors in the shed (no sun), or bringing them in with my hot pepper overwinters, which are kept actively growing. I am leaning toward leaving them outside, but wonder if there are any dangers to that.

A: It would be best to leave the plants outside this winter. It’s getting too late to transplant them directly into the ground now, but you can leave them in the pots over the winter and plant them in the ground in the early spring. However, since the plants are currently in pots, the roots will be exposed to colder temperatures than if the plants were in the ground. (The soil insulates the plant roots against the coldest temperatures and reduces temperature swings.) The plants will be likely to suffer severe winter injury. With potted plants, I generally suggest that clients simply dig a hole in the garden, “plant” the pots as is for the winter, back filling around the pots, apply mulch (such as leaves, straw, evergreen boughs) after the ground freezes, and then take the pots out in the spring. Since your pots are decorative, you could put the pots in a protected area, and once we’re having hard freezes, bank them in with evergreen boughs or many leaves to insulate them.

Q: Last weekend I wanted to to give the perennial and biennial beds a little food before winter and accidentally put 0-46-0 on at two cups instead of one per 100 feet. There are about 3 inches of wood chips/shred on top of the soil and we haven’t gotten much rain this week. Should I shop vac up what I can or do you think it’s okay to leave it? There are several baby cone flowers and columbine in the bed and I just dug up the very overgrown iris and replanted the best bulbs. The only fertilizer the garden has had this year was 10-10-10 before the spring rains, and last year it only got 10-10-10 early in the season with no fall fertilizer. I know you can’t tell me definitively without a soil test, but your best guess would be appreciated.

A: I would just leave the extra fertilizer where it is. I would not expect that a single over application of phosphorus to cause any problems for your plants. Excess phosphorus may lead to reduction in uptake of iron and zinc, but that would be more likely to occur if the levels were already very high in your soil

Q: I have a bunch of tomato plants that grew out of some compost I put around pepper plants. These tomato plants are producing lots of small round tomatoes! I am wondering what kind they might be and if I can dehydrate them by slicing thin and if I should remove any seeds? They are about the size of golf balls.

A: If the tomatoes are growing out of home-made compost, they are likely growing from seeds from tomato scraps that went into the compost. As such, they are showing traits of both parent plants, but they are not exactly the same as either parent (which we would guess are named varieties). If they taste good, then definitely eat them! As for how to dehydrate the tomatoes, a great resource is Resources for Home Preserving Tomatoes from the National Center for Home Food Preservation.

Red Osier DogwoodQ: We are trying to clear invasives (multi flora rose, bittersweet) from a culvert/gully area on our property. Those are easy to identify but I’m coming across a lot of the plant in this photo (at left). Most have red stems but others with the same leaf structure are green, and it appears to grow off runners. Is it a red twig dogwood or osier or in that family?

A: The plant in the photo you sent appears to be a Red Osier Dogwood. It is a native plant so that is a good thing.

beetlesQ: I found about four of these beetles/bugs on my anemones yesterday (see photo at right). We thought they were oil beetles but aren’t sure with the color and abdomen. One was larger than the rest. All we’re eating away on my anemone. I squished them all with a shovel.

A: The insect is in the blister beetle family and is in the genus Meloe. This group is often called the oil beetles, as you suspected. If you crush the insects with your fingers, they can give you a chemical burn, so the shovel assistance was a good idea.

ImpatiensQ: I have been growing impatiens in flower boxes on my deck this summer. They’ve done spectacularly well this summer in the sun but this week I’ve noticed that one of the boxes has plants that are looking pretty bad. They have enough water but they are very ratty looking. The other two boxes are still looking okay, but all three boxes have plants with a powdery coating under the leaves. Sometimes the coating looks like smoke coming from the leaves when they are disturbed.

I am not sure why I’ve got what looks to be mildew when it’s been so dry. I really like these plants but I am not sure about planting them in the boxes next year. Can I use the same boxes with fresh soil next year? What can I do to prevent this from happening next summer?

A: To properly identify the problem and give complete management recommendations, we will need a physical sample. Sampling instructions, shipping address, and packaging information can be found on the University of Maine Cooperative Extension’s Diagnostic Laboratory website. Our pathologist will review the history, examine the plants, and look for specific signs of a pathogen, such as spores, which she can identify using a microscope.

We don’t generally recommend re-using potting soil from one year to the next. Some diseases, such as impatiens downy mildew (which could be what is affecting your plants), have spores or other resting bodies that can survive in the soil/potting mix for many years. If your containers are plastic or clay and you do want to re-use them, be sure to sanitize them before re-using. First empty the containers. Then, wash them in warm, soapy water, scrubbing out any remaining material. Rinse them, then soak them for 10-30 minutes in a 10% bleach solution (1 part bleach for 9 parts water). Finally, wash in soapy water (clay) and rinse them thoroughly.

While many foliar diseases need wet weather in order to thrive, others can do well under conditions of dampness or extended periods of leaf wetness, even without rainfall. This summer has been dry, but many parts of the state have had damp or foggy nights and early mornings recently. The damp nights are enough to really accelerate the growth of many foliar diseases.

Killarney raspberriesQ: What kind of fertilizer should I put on new raspberries this fall?

A: The University of Maine Cooperative Extension fact sheet Growing Raspberries and Blackberries is a great resource for raspberry production. From that fact sheet: “Raspberries should be fertilized each year in the early spring (mid-April). Apply 20 pounds of 10-10-10 (or organic equivalents) per 1,000 square feet of the planting. Increase the rate to 25 pounds if a heavy mulch is being used. It is best to split the application, applying half of the recommended amount in mid-April and the second half four to six weeks later.”

Q: My small apple tree had white fuzz all over it, including at the very bottom by the soil. I just washed all of the branches and trunk with warm water and dishwashiung liquid. When I washed it, the water turned raspberry color with all kinds of black dots. Will this help, or will I lose my tree and could you tell me what I am dealing with?

A: There are a couple of pests that would be causing the symptoms you mention. We will need a physical sample to correctly identify the pest and give control recommendations. Sampling instructions, shipping address, and packaging information can be found on the University of Maine Cooperative Extension: Insect Pests, Ticks and Plant Diseases website.

strawberriesQ: How do I grow strawberries in northern Maine?

A: Basic information can be found in the UMaine Extension publication Growing Strawberries. This online publication includes videos about planting, preparing for winter, renovating old stands, and growing strawberries in the off-season. Site selection and preparation are very important, and many gardeners find it helpful to start preparing the site a year before planting. Strawberrry Varieties for Maine will help you choose the varieties that have the harvest timing, size, and flavor that you prefer.

puffball fungusQ: Can you identify this fungus please?

A: I suspect this fungus is a giant puffball that is misshapen due to the dry conditions we had over the past week. Giant puffballs are edible when thoroughly cooked and when they are completely white internally. Since this is a very unusual specimen I cannot confirm the identification from the photo and would NOT recommend eating it.

Q: Last week, I came across a garden plant that I cannot identify and I am hoping you will know what it is. I am sending you pictures I have taken of the plant in the garden as well as those of the seeds and pod that I picked. Please let me know if there is any other information I can give that might help identify this plant.

A: It took a little while and some help from colleagues at the Maine Department of Agriculture, Conservation, and Forestry, but it looks as though the plant could be Dictamnus albus (Gas Plant). In another email, you mentioned that you might be interested in growing out these seeds. If the identification is correct, and if you do grow the plant, be aware that contact with the plant can cause a burning rash and blisters in sensitive individuals. Curiously, the plant produces volatile oils that can be lit on fire on a still day, hence the common name of “gas plant.”

Japenese KnotweedQ: I have a large bush (please see photo). Should I leave it and prune it back, or if I should get rid of it, what is the process?

A: What you have goes by the names of Japanese knotweed or Mexican bamboo (Fallopia japonica). Its biology and management are described in the University of Maine Cooperative Extension bulletin Japanese Knotweed/Mexican Bamboo. Japanese knotweed is a non-native, very invasive plant. It is very difficult to control once it gets established. It spreads by seed (you can see the whitish flowers in your photos) and also by rhizomes (underground stems). It is a perennial plant, meaning the same plant comes back year after year, although the leaves and stems die back each winter. Since your patch is still relatively small, you may be able to gradually control it with repeated cutting. Three times a year is a minimum, but more frequently will deplete the underground resources faster. Over time, this will kill the plant. Digging isn’t recommended, since the plant can spread by root fragments. Depending on the specifics of the location and your philosophy, you may also want to consider using a herbicide, such as glyphosate. This may be applied to the entire plant in the late summer or to the cut stems just after cutting. Consider the surrounding vegetation and proximity to sensitive areas such as streams or lakes when deciding if herbicide use is appropriate. Always read and follow label directions. Here is additional information about managing Japanese knotweed.

plumsQ: I want to plant a fruit tree in my garden. I am not sure what trees grow well in Maine in the Casco Lake area. Can you please send me a list of the recommended fruit trees and the best time to plant them?

A: When choosing a type of fruit tree, first consider what plant hardiness zone you are in. You can get a sense of this from the map in University of Maine Cooperative Extension’s Plant Hardiness Zone Map of Maine. Keep in mind that there are many local microclimates that may make your temperatures warmer or cooler than average for your area. From there, take a look at the tree fruit type and variety recommendations in University of Maine Cooperative Extension’s publication Growing Fruit Trees in Maine. If your average low temperatures put you in the 4b zone (typical for the Casco area), options would include apples, pears, plums (certain varieties), tart cherries (certain varieties), and peaches. If space is limited in your garden, look for fruit types that can be grown on dwarfing rootstocks, and seek these out when making the purchase.

As for planting time, bare-root trees should be planted as soon as possible in the spring. If your trees are in containers, you can hold them a little longer, but spring-planted trees will establish best. Again, earlier is better. Keep the trees watered, if needed, following the recommendations in Growing Fruit Trees in Maine.

Q: I know one should not pick pears before they are ripe. How can I tell the correct time to pick them?

A: You are correct, European pears should be picked when mature but not yet fully ripened. Otherwise the fruit may be mushy or rotten on the inside before the outer flesh is soft. (Asian pears can ripen on the tree). Firmness and color are not good indicators of ripeness. It is best to see if the fruit comes easily off the tree. Tilt a fruit so that it is horizontal to the ground. If it comes off the twig easily, it is ready to harvest. If it does not come off easily, it needs more time. From there, the pears will ripen fully in about a week at room temperature. For more information about growing pears, see University of Maine Cooperative Extension’s Growing Fruit Trees in Maine and University of Minnesota Extension’s Growing Pears in the Home Garden.

gourdQ: Could you please tell me what vegetable is in the picture? Is it ornamental? Should it have been picked at this time or will it get orange? I have a huge plant growing from my compost pile.

A: Your fruit looks like a type of pumpkin, squash, or gourd. If this fruit is growing from a plant in your compost pile, it may have grown from a seed from one of last year’s fruits. As such, I can’t be sure what the mature fruit will look like or whether or not it will taste good. Depending on the type of squash the parents were, the offspring can be very different! Once the outer skin is tough (difficult to cut with a thumbnail), then it is mature and ready to harvest.

Q: I would like to start a new bed in a full shade area. Is it okay to plant a new bed in the fall, or should I wait until spring? There are only a couple of small rhodies. I would like to plant Goatsbeard, Turtlehead, hostas, ligularia, May flower, bleeding heart and Solomon’s Seal. Usually I plant in May/June, but eager to get started, so I’m wondering about autumn planting.

A: The best soils for this type of bed would be a sandy loam with moderate fertility. Since there is not much growing on the site at the moment, site preparation will be simple, primarily consisting of taking a soil test. See UMaine Extension bulletin Testing Your Soil, amending the soil as recommended. Given that, and for most of the plants you are considering (Goatsbeard, Turtlehead, hostas, ligularia, May flower, Solomon’s Seal), a September planting should be fine. Be sure the plants get 1-2″ of water each week (from nature or hand-watered) until late October. Once the ground is frozen, lay pine boughs over the plants’ crowns so they don’t heave during the winter and spring. Remove the boughs when new growth begins in the spring. You also mentioned that you’d like to divide and share your bleeding heart. That’s one that is likely to do better with an early spring division.

Q: A couple of weeks ago I saw a blueberry bush that would probably be classified as a tree. It was huge! The trunk was maybe 6″ in circumference and it was 12′ tall. What species of blueberry grows that tall?

A: Yes, blueberries, can sometimes get as tall as 12 feet. However, they are multi-stemmed shrubs and I would not expect any single cane to be 6″ in circumference. If you can send along some digital photographs, we may be able to better identify the plant you saw. Those photographs should include pictures of the plant in the landscape, some closer-up photos, and photos clearly showing the arrangement of the leaves on the stems, the leaves themselves, any flowers, and any fruits. Using the close-up, zoom, or macro setting on your camera will help. A physical sample (small branch) can aid in the identification, if you are able to collect one from the site.

apples on treeQ: How can I start apples from seed? I have gotten several apples from beautiful and very old trees and would like to try and grow them. Is this even possible?

A: Apple varieties are hybrids. The seeds produced will contain genetic material from both the parent tree and from other trees contributing pollen. Therefore, the seeds will not grow plants that are the same as the parent tree. To grow that same type of apple, you would need to take cuttings and graft them on to a rootstock. The process is briefly described in the Rootstocks section of the UMaine publication Growing Fruit Trees in Maine.

Q: Crab grass is driving me crazy. We moved to Yarmouth last year. My husband did a weed/feed on the lawn and part of the pasture from which crab grass seed jumps into my perennial and vegetable gardens. The application did nothing. Short of hand-weeding the yard and pasture, what do you suggest?

A: Although it is a long-term strategy, maintaining a good stand of perennial grasses in the lawn and pasture is one of the best ways to combat crabgrass. To do this, keep mowing height high (3-3.5″), irrigate your lawn deeply if the weather and soil conditions dictate it, and fertilize your lawn with 1 pound of nitrogen per 1000 square feet around Labor Day. Please see the following publications.

The following Extension bulletins give specific recommendations for managing crabgrass in lawns after it emerges.

Be aware that the plants are quite large now and will be difficult or impossible to control with herbicides.

Call your local UMaine County Extension office if you need herbicide or management recommendations for a pasture that is being actively used for grazing. Be aware that crabgrass can be good forage for your animals. You may need to adjust grazing or mowing patterns in order to keep the crabgrass from going to seed.

You mention that a weed/feed treatment was used in the spring. If you are considering another application next spring, double-check the label to be sure the herbicide it contains is effective against crabgrass. Some weed and feed materials contain broadleaf herbicides, and those will not be effective against crabgrass. Always read and follow label directions.

Japanese Beetle
Japanese beetle; photo by Charles Armstrong

Q: I have been fighting Japanese beetles for close to 3 weeks with a mixture of vegetable oil, alcohol, dish soap, and water, which does not help much. I also walk around hitting the beetles into a bucket with water. I have heard of milky spore powder. Does it work? I have under an acre of land. Do I have to put it all over my grass or just near the rosa rugosa? Will I need to apply it more than once? What time of year is the best to apply this?

A: Japanese beetles can be very frustrating to deal with. For detailed information about the insect’s lifecycle and control, see UMaine Extension’s Pest Management Fact Sheet on Japanese Beetles.

The handpicking you are already doing can help to reduce insect numbers and damage. Pheromone/bait traps may be helpful, although they may also attract more beetles to the area. If you use them, be sure to put them at least 50 feet away from the plants you are trying to protect. Empty the trap as soon as it is full. Effective foliar pesticides include pyrethrins, neem, kaolin clay (Surround), cyfluthrin/imidacloprid, malathion, and carbaryl (Sevin). Be sure to read and follow all label directions. Repeat applications may be needed. In future years, depending on the size and type of plants affected, you could consider cover them with insect barrier-weight row cover or other fine-mesh fabric in order to physically exclude the beetles.

As for your specific question about using milky spore, there are two challenges. The first is that controlling the grub stage of the Japanese beetle in one home landscape usually will not reduce the later adult populations. The reason for this is that the adults are strong fliers, and they will fly to your yard from surrounding areas. The second challenge with milky spore is that it has not been found to be effective at controlling Japanese beetle grubs in northern New England.

HummingbirdQ: Growing up in California, our tomato plants were always infested with the tomato hornworm. I’ve been in Veazie, Maine for about 20 years and have never seen one in my garden. Last night however, I saw what I thought at first was a very small hummingbird feeding on my hanging flower baskets. Upon closer observation, it wasn’t a hummingbird, but was what I think is a hummingbird moth which is part of the lifecycle of the hornworm. I’ve asked my friends about hornworms and they have never seen one here in Maine, yet I know what I saw appeared to be a moth! Does Maine have hornworms and are there hummingbird moths here?

A: Yes we do have hummingbird moths and Tobacco and Tomato Hornworms in Maine. Now is the time of year when the moths are laying eggs and the larvae are growing and eating tomato leaves. Here are some links to fact sheets on hornworms.

Red Maple LeafQ: I purchased a red maple in June from a reputable nursery. The trunk is approximately 2″ in diameter. In July, I noticed tiny red nodules on the leaves, which now have turned into maroon/black splotches. I believe they are gall mites. Several articles that I’ve read said they leave only aesthetic damage and do not harm the health of the tree. The articles also said to not bother trying to treat it — that it will just come back and isn’t worth it. I would like my tree to not have any aesthetic damage so I was wondering how exactly you “treat” this. Should I just call an arborist or is there a home treatment or something I can purchase myself to treat this?

A: It is correct that gall mites are aesthetic and do not set the trees back at all. In order to recommend a treatment we would need a specimen sent to our Pest Management Office so we know which gall mite or disease organism is causing the problem. Send an affected leaf sample in a plastic bag and bubble envelope or small box to: Pest Management Office, 491 College Ave, Orono, ME 0473 and we can diagnose it free of charge. Please list your name, contact information including email, the plant variety, and extent of the damage.

From your picture, the red maple looks like an invasive Norway Maple, which by law should no longer be planted in Maine as they cause a lot of harm when the seeds spread to the wild and displace native species. Do you know if this is considered a Norway Maple, Acer plantanoides? If so, we would recommend removing it.

Q: I have two pear trees about 5 years old that never blossom. What can I do?

A: It could be that they are not yet mature enough to start blossoming. Other things to consider, are the trees getting full sun and/or is the soil and location appropriate for fruit trees? For more information please read our Extension fact sheet on Growing Fruit Trees in Maine.

If you would like to do a soil test, visit or call your local UMaine County Extension Office to request a soil test box and form which you then send into our soil lab at UMaine. Feel free to call me at my office if you have further questions at 207.324.2814

flowers
Photo by Amy Witt.

Q: In planning for next year’s small flower bed, I am interested in learning about early to late spring blooms, early to late summer blooms, and early to late fall blooms. Essentially after the daffodils and tulips fade, I’d like to have other plants take their place, a staggering effect. Is there a book you could recommend that shows how to keep a cycle of flowers in the growing seasons?

A: I would recommend a book called, The Ever Blooming Flower Garden: A Blueprint for Continuous Color.

Q: Last night two of my cabbages split. I just read the the dry weather followed by rain can cause this. My question is can these cabbages be used to make sauerkraut?

A: Yes, as long as you take a clean sharp knife and cut off a thin slice where it is split inside to make sure you have taken out any rot that may have set in. For more information on sauerkraut please read, Sauerkraut: From Garden to Table.

Q: Recently some squirrels have decided to start terrorizing my squash, corn, and soil that I just seeded with more butter bowl lettuce. I have tried the store sprays that have peppermint oil, safflower oil, and cayenne. If anything, I think it is attracting them!!! All my vegetables are planted in raised beds and near a fence. Any suggestions would be much appreciated!

A: That is a tough question as there are no easy solutions. The only really effective method would be exclusion with a fence which is cost and time prohibitive for a lot of people. There are repellents but as you have experienced squirrels that are hungry and don’t have an abundant food source elsewhere are more likely to overcome the repellent once they know the rewards to be had. Of course there is also trapping and or shooting but check with your local town office for any ordinances and with your regional office of Inland Fisheries and Wildlife for rules on trapping.

For more information on repellents and trapping please contact the USDA Wildlife Services – Maine office (PDF).

Another great resource is the local Maine office of Inland Fisheries and Wildlife.

Client photoQ: There is an abandoned lot in my neighborhood with a fruiting tree. The berries look a lot like elderberries and have red stems, but they are not in the big bunched clusters that I associate with elderberry. Can you help me identify what these are?

A: The plant in the photo is Prunus virginiana and is known locally as chokecherry. The fruit are edible but don’t taste very good. But could be used for jams and jellies. It is a native small tree and wildlife love it for the berries and also many native pollinators benefit from eating some of the leaves and fruit. For more information please see Prunus virginiana.

Q: I have tiny worms (about 7 cm long) on the cones of Echinacea and Heliopsis flowers. What are they and what should I do to get rid of them?

A: Seven cm is almost three inches, which I would not call a tiny worm. It is really impossible to tell without either a good photograph (which you are welcome to email to your local UMaine Extension county office) or by collecting a specimen, place it in a small vial with some rubbing alcohol and send it to our Pest Management Office for identification (Pest Management Office, 491 College Ave, Orono, ME 04473). Only through identification can we recommend a control.

80th day

Q: My question is what to do with potatoes that are ready to harvest, in the middle of summer, without any cold storage for storing them?

I’m at the finish line of my first time growing fingerling potatoes in containers. I have ten 27 gallon containers growing five different verities (four containers early — mid 80-90 days) of “fingerling” potatoes. I’ve added or hilled soil as the greenery grew twice. August 1st, will be the 90th day since planting, which coincides with the seed company’s days to harvest. But it’s the temperature in my basement of 68 degrees at floor level that has me scratching my head. Currently, I have a couple of inches of straw mulch atop of the soil.

Obviously, I don’t want chits to start within a month or two. Nor do I want them to start shriveling up and softening if I harvest them and put them into storage. I’m wondering if my best alternative is just to leave them where they are till mid September or so. If so, do I water them even if the greenery has browned?

This has been a fun project. Initially it was a lot of work. I’m looking forward to the future years of just planting instead of setting up the gardening space.

Before closing, my plan is to start emptying one container at a time enjoying and giving away early potatoes. As I empty each container I plan on returning the soil to the container, plant some radishes & beets while making a mini hoop house over each vessel. Is this okay practice as far as rotating or not rotating crops? What if I use the same soil next year to grow the same potatoes?

A: It sounds as though you’ve had a lot of fun with these potatoes! If you’re hoping to store these potatoes, you need to give the skins time to toughen up (to “set”). You can either wait until the tops and stems die back on their own, or you can cut the vines off to start the process. Once the vines are dead or removed, leave the potatoes in the soil for at least a week (typically 1-3 weeks), during which time the skin will set. Warm soils will actually help speed this process. Keeping the soil damp but not wet will also help. The tougher skin will reduce tuber damage during harvest and will also reduce post-harvest drying. You can leave the tubers in the soil for longer than the typical 1-3 weeks, but be aware that they will be more likely to develop tuber diseases, such as silver scurf and black scurf (Rhizoctonia), if these pathogens are present in the soil. Harvesting when the temperatures are below 55 F can increase bruising. Harvesting when the temperatures are above 80 F can lead to greater incidence of storage rot. Once you do harvest the tubers, keep them as close to ideal conditions as possible (38 degrees F, 95% humidity). You may need to do your best with a cool, damp basement. The UMaine Extension publication Growing Potatoes in the Home Garden can give you some other production pointers for next year.

It should be fine to use those same containers and soil for beets and/or radishes this fall. As for next year, if you re-use the same soil for potatoes again, you may see reduction in growth and yield from soil-borne diseases. If possible, use this soil to grow something other than potatoes or crops in that same family, which includes tomatoes and eggplants.

Q: What is eating the leaves off of the Alder bushes this year? It is really doing a number on my trees in Brooks. They are dark brown to black in color almost look like rodent droppings in a way.

A: From your description, it sounds like the larvae of alder flea beetles are feeding on your alder leaves. All in all, these beetles considered to be minor pests of well-established alders, as infestations occur only occasionally. Chemical control is seldom considered necessary in landscapes.

If the tree is young and was recently planted, you may want to remove as many of the larvae as possible. Insecticidal soap will work when used according to label directions and sprayed directly onto the larvae. Or you can wage one-to-one battle by flipping them into soapy water.

Here is further information from Oregon State University about the alder flea beetle.

Q: I have two older apple trees. One is a Wolf River. Every year the apples are useless because they are riddled with brown tracts, and an occasional tiny whitish worm. We had the trees sprayed a few years ago with an orange spray, and then an insecticide-type spray the next year. Neither spraying improved the situation.

The apple maggot larva creates brown
tunnels in the flesh of the apple.

A: What you are describing sounds suspiciously like apple maggot. The following information is excerpted from our Growing Fruit Trees in Maine website about apple maggot. Both conventional and organic management methods are described.
The apple maggot larvae feed on the flesh of the fruit leaving a brown trail inside the apple in late summer. They overwinter as pupae in the soil and emerge in late June and July. Approximately ten days after emergence, the females begin to lay eggs in apples. They favor apples and plums.

Eggs and larvae are protected from insecticides and repellents since they are inside the apple. When insecticides are used to prevent damage, they should be applied just before egg laying occurs. Insecticide applications, starting in mid-July, with a renewal application in late July or early August, and a final application in mid August, are usually adequate to prevent apple maggot infestation. The final application may be omitted for earliest ripening varieties, and the first application maybe omitted for the latest ripening varieties. Insecticides should not be applied right before harvest. Esfenvalerate cannot be used within 21 days of harvest. Carbaryl (Sevin™), tree fruit spray and phosmet (Imidan) cannot be applied in the week before harvest.

Red colored spheres, coated with the sticky substance, Tangletrap™, can be used to trap apple maggot adult flies.

Red spheres the size of a large apple and covered with the sticky substance, Tangletrap™, can be used to trap adult flies. At least one trap for every 100 apples is needed to adequately prevent infestation. Use one trap on a dwarf tree or four traps on a semidwarf tree. Place traps in the orchard the first week of July. Traps should be completely covered with Tangletrap™ and hung from a branch in the outer part of the tree, surrounded by fruit, but not hidden by leaves.

The repellent Surround™ can be used in conjunction with traps or on its own for apple maggot. However, Surround applied to fruit in August may still be on the fruit at harvest and should be washed off before consuming the apple.

 

Q: I keep noticing these small bugs on the leaves of my eggplant. They are having a field day with the leaves. I take them off and a few days later, they are back. The strange part is that I am only finding them on one of the plants, when I have several other eggplants growing right next to the one being attacked. Any suggestions on getting rid of them without pesticides?

potato betle
Larvae of the Colorado Potato Beetle.

A: The insects in your photo are the larvae of the Colorado Potato Beetle. Both larvae and adults feed on the foliage of plants in the nightshade family (Solanaceae), which includes potatoes, eggplants, tomatoes and peppers. The adult is an oval shaped yellowish white beetle with black stripes. In a small home garden they can usually be controlled by hand picking if you are diligent. Scout your plants every day (several times a day if you can), and knock the larvae and adults into a pale of soapy water. Look on the undersides of the leaves for clusters of yellowish orange eggs. Fold the leaf over and crush the egg clusters when you find them.

Colorado Potato Beetles can overwinter in the soil, so next year, plant your solanaceous crops in a different area of the garden. When the plants are young, you could protect them by keeping them covered with a spunbonded row cover. Just be sure to uncover them when they bloom so that they can be pollinated.

For more information please see  Colorado Potato Beetle in Home Gardens (PDF).

Q: Do high bush blueberry bushes bear heavily every other year as fruit trees do?

A: Once a high bush blueberry plant is established in your landscape (after four years), if it has been properly sited and is pruned annually, it should bear a crop of fruit every year. If left unpruned, blueberries habitually over-fruit, which decreases fruit size and quality; delays maturity; and can set plants up for biennial bearing. For instructions on how to properly prune your high bush blueberry bush, see our instructional Pruning Blueberries video.

maple tree

Q: I have a 3-year-old red maple in my front yard, which has developed something that is turning the new growth into a black mass that just crumbles in my hand. Some of the leaves are also looking odd. Can you help with the problem?

A: I suggest that you prune out the affected branches and dispose of them in a sealed trash bag; do not let the diseased plant material lie on the ground underneath the tree. When you prune, cut back into 6″ healthy growth, and make your cut just above a side shoot (don’t leave a stub).

To get the disease identified, we will need you to bring a sample into your local County Extension Office, or send it directly to our Pest Management Office with the following form (PDF).

Q: Can you identify the insect or disease that is damaging the fruit of a Yellow Transparent apple tree? Also, how to rectify the problems? This is the first year the tree has borne fruit. Another Yellow Transparent apple tree is 40 feet away, and the apples on that one are okay. A Macintosh tree is between the two Yellow Transparents. The trees are about nine feet tall and were planted about five years ago in soil that is rather poor with some clay in a southerly field.

apples damaged by plum curculio (client photo)
Apples damaged by plum curculio.

A: The damage on the apples appears to be from plum curculio egg laying and feeding. Next year apply an insecticide that is effective against plum curculio after the petals fall, and again ten days later. There are many non-organic options sold as home fruit tree spray mix. The insecticide in most of those mixes is effective against plum curculio if applied at the right time and according to label directions for dose.

Neem and Bt are not effective against plum curculio. The only organic option that might be effective is an organic formulation of spinosad. One is sold by Monterey.

Another organic option is Surround clay but that requires about 4-6 applications over a six week period, starting at petal fall and until early July for best efficacy, and even then it may not give as good control as insecticide.

To reduce the plum curculio population for next year you could remove fallen fruit but it’s probably too late for that to be effective as the larvae probably already left the fruit and has gone into the soil. Most of the plum curculio are most likely immigrating from other sources so controlling them in the ground of your yard may not make that much difference anyway.

There are many non-organic options.

Q: We had leafminers last year and they’re back again and seem to be in all five of our raised beds now! We do a lot of cleanup of yard and beds in the fall, so it wasn’t like there was a lot of debris, etc. left over. How can I get rid of these pests so we’re not troubled by them again next year?

A: Leafminers in the vegetable garden are the larvae of small flies that overwinter as pupae in the soil. In the spring, the flies emerge and insert eggs into leaves. Larvae feed and develop within leaf tissue. The larvae are active for about two to three weeks, feeding within the leaf tissue before dropping to the ground and pupating in the soil. Several generations can occur during one year. Leafminers don’t have much impact on plant growth, but if you are growing leafy greens like spinach or Swiss chard, they definitely affect the crop. There are non-chemical ways that you can manage them. Remove infested leaves as soon as you spot them, when miners are small. Keep up with the weeding in your garden, removing other potential host plants for leafminers. Turn over your soil after you’ve finished gardening to expose the pupae to predation by birds and others. For more information see the University of Minnesota Extension’s bulletin Leafminers in Home Vegetable Gardens.

Q: I have had raspberries for many years. I always cut the canes that produced berries back in the fall. This year about 15 of the raspberry canes are dead. Any thoughts?

David Handley stands beside a row of properly pruned raspberriesA: A well kept raspberry planting can provide fruit for 10 – 20 years, but viruses, fungi, and several types of insects can kill canes.

Many problems can be prevented by proper planning and care. If possible, destroy all wild brambles within 600 feet of the planting. Encourage good air circulation by having at least 8 feet between your plant rows and keeping each row to a 12- to 18-inch width. Prune your plants regularly to promote healthy new growth and reduce the spread of diseases. Keep the planting weed-free to discourage insect pests and prevent competition for water and nutrients.

See our bulletin Growing Raspberries and Blackberries, which includes short embedded instructional videos, on growing raspberries in Maine, for tips on how to best care for your planting.

For specific pest identification and management techniques, contact your University of Maine Cooperative Extension county office.

Q: Can I grow edible crops over part of a septic tank leach field?

grassy septic fieldA: Although the leach field may be the sunniest spot on your property, it is not the best place for a vegetable garden. Liquid effluent, or wastewater, is separated from solid waste and flows from your septic tank into a series of drain lines that allow it to slowly percolate down through the soil in the leach field. Even though different soil types differ in their ability to filter contaminants out of the effluent, there is no way to be absolutely sure that everything is being filtered out. Therefore it is not recommended to plant vegetables in a septic drain field because of the health risks associated with bacterial contamination. Also, vegetable gardening requires frequent cultivation of the soil, supplemental watering, and fertilization. None of these practices are recommended for a drain field. Using a raised bed is also not recommended. The additional soil over the drain field reduces the effectiveness of the system to filter the effluent because it interferes with evaporation of soil moisture.

Below are links to two Extension publications that explain leach fields and recommended plantings for them.

ArtemesiaQ: We have a plant that is taking over our flower garden and is heading via a root system into our vegetable garden. We have been trying for the better part of 4 years to remove it but it just keeps on coming back each year even stronger. We have discovered this year that it has a very strong root system that seems to travel under the ground. Could you please give us advice as to the best approach to remove this invasive plant?

A: The plant could very well be an Artemesia. Since we know it is an aggressive herbaceous perennial, and it spreads by rhizomes (underground stems), I suggest you use multiple strategies to control it.

  1. Do not allow it to flower and produce seed. Seeds will produce more plants.
  2. Cut the foliage back to the ground, then dig out as much of the rhizomes and root system as you possibly can. Dispose of this in a thick plastic trash bag, not in your compost pile. Small fragments of the underground stems will re-root, so be thorough and meticulous.
  3. Over time, if anything is left behind, it will resprout. Dig it up again and dispose of it.
  4. If you absolutely cannot remove it all from digging, and it continues to resprout, you could try spot treating the remaining foliage in the early fall with a systemic herbicide containing glyphosate. Be sure to follow the directions on the pesticide label carefully.

liverwort/client photoQ: I am attaching a photo of a ground cover that is taking over my garden in the hope that you can identify it and tell me how to get rid of it. It grows very fast. The leaves are kind of waxy and heart-shaped. The main leaf in the photo has about an inch between the small circles.

A: What you have growing in your garden is a type of liverwort, a prehistoric plant that typically grows in a shady, moist environment. Liverwort is sometimes a serious problem for large-scale growers of container plants and greenhouse growers. Research showed that drying the surface, then mulching, limited it. Nowadays, that’s the reason many pots are mulched with gravel or filbert shells.

In your garden:

  • As much as possible, allow the soil surface to dry. Perhaps water less often, but longer for each session, so that your desirable plants continue to thrive.
  • Use fertilizer judiciously, reducing the amount you use and, when you do use it, place it around individual plants that need it, then lightly scratch it into the soil.
  • Because liverwort has shallow roots, it’s easily scraped off the soil surface; then add an inch or two depth of mulch of your choice.
  • Repeat the above as needed, while realizing you must be persistent. It’s important to know that most herbicides won’t work. The reason: liverwort isn’t a vascular “plant.” Then, too, no home-use products are labeled for liverwort.

“Liverwort” from the Oregon State University Department of Horticulture was written for commercial operations, but is helpful information. For more general information, see liverworts, which are actually quite interesting plants!

Q: Our lawn is being taken over by creeping Charlie. We do not want to use weed killer. What other ways can we rid our lawn of these plants?

A: Also called ground ivy, creeping Charlie is part of the mint family. Like all mints, it spreads at the ground surface via stolons (horizontal stems). It will regrow from very small pieces of vegetation left behind in the soil after removal. It is a very adaptable plant and grows well in moist soil in part shade / full shade sites. Creeping Charlie can be found where lawn grass is thin and not very robust. This may be in compacted soils, shady locations, and weedy sites.

Maintaining a healthy lawn, utilizing shade tolerant grasses, and choosing alternative ground covers in areas not suitable for growing lawn grasses will help manage weeds including creeping Charlie.

Please consider having your lawn soil tested, as you may need to adjust the pH. You can pick up a soil test kit at any University of Maine Cooperative Extension Office. You can watch our instructional video on how to collect a soil sample and read our bulletin on Testing Your Soil.

If creeping Charlie isn’t yet widespread, you can control it just by consistently pulling up and discarding all parts of the plant. Do not toss any stems or roots into your lawn, as they will take root and spread further.

You can try to shade out the creeping Charlie by setting your mower at a very high setting (3 – 3.5″) and letting the grass block the light, mowing high (PDF). If you mow low, you will chop Charlie into tiny bits and throw them back out into your lawn where each tiny bit has a chance to set roots and grow.

Another approach is to cover the area with heavy cardboard, many layers of newspaper or a piece of old carpet. Weight it down with soil, some stones or boards to keep it tight to the ground so no sunlight can enter. After at least one week, take a peek. If the creeping Charlie looks like it still has some life left to it, cover it again for another week.Once it is dead, rake the dead vines and foliage, then reseed.

Q: My lawn has been overtaken by crabgrass. I did put down pre-emergent when the forysthia was out, but it did nothing. Also, how can I get my soil tested?

A: We do not recommend that you attempt to control crabgrass with herbicides after mid-July because crabgrass plants are usually too large to control effectively. It is better to simply tolerate the crabgrass until it dies with the first frost. Meanwhile, do what you can to maintain a dense lawn by mowing high (PDF) (3 – 3.5″), irrigating your lawn deeply and Fertilizing your Lawn in Maine with 1 pound of nitrogen per 1000 square feet around Labor Day.

The following Extension bulletins give specific recommendations for managing crabgrass in lawns after it emerges.

Regarding testing your soil, you can pick up a soil test kit at any University of Maine Cooperative Extension Office.

Be sure to watch our instructional video on how to collect a soil sample and read our bulletin on Testing Your Soil.

strawberry spinach/Chenopodium capitatumQ: Can you help identify this plant growing in a Portland garden?

A: I believe the plant in the photo is “strawberry spinach,” Chenopodium capitatum. It is native to Maine, and the leaves and fruit borne in the leaf axils are edible, though not very rich in flavor. Some references say that it can become a weed problem in the garden if allowed to set seed. You can find a little more information about this ancient plant in the Pinetree Seeds Catalog.

polygonum cuspidatumQ: Can you tell me what type of bush this is? It grows wild near my home in Maine.

A: The plant in the photo you submitted is Japanese knotweed, Polygonum cuspidatum, also commonly called Mexican bamboo. It is a very common, aggressive, non-native invasive species in Maine. It is a very challenging weed to manage once it gets established on your property because of its tendency to quickly form large colonies. It is not a woody shrub, but rather, a herbaceous perennial that dies back to the ground every winter and resprouts from rhizomes (underground stems) in the spring.

The best method of controlling this species is to prevent it from becoming established. It should be removed as soon as possible if it is found colonizing an area. Once well established, it can be eliminated by repeatedly cutting the stalks. Three or more cuttings in a single growing season can offset growth of the rhizomes. An alternative is to cut it down repeatedly and apply glyphosate to the remaining part of the plant. Digging up the roots is not suggested because digging can lead to root fragments that can repopulate the area.

For more information about this plant, please see the following website, Japenese Knotweed.

Q: My cucumber plants are playing host to striped cucumber beetles. Most of the plants are about 1 month old. Handpicking has worked to a point since they are easy to catch but they are prolific. I’ve read the fact sheet link on this site, which prompted these questions. Will row covers help at this point? Will the suggested insecticides help at this point? If, as the fact sheet indicated, the larvae are eating the roots, is it too late for any remedy?

Striped Cucumber Beetle
Striped Cucumber Beetle; photo by J. F. Dill

A: If you already have cucumber beetles on the plants, using row cover will trap them underneath, where they will continue to feed and lay eggs. Row covers are best applied immediately after planting. If we wait to put the row cover later, we’re often too late! Row covers should be removed when the plants start to flower to allow access to pollinators.

As you mention, UMaine Extension’s Striped Cucumber Beetle fact sheet outlines different management methods, including insecticides. These insecticides will be relatively effective, but may miss a few insects. A potential strategy at this point would be to use an appropriate insecticide, then cover the plants with row cover. If you do that, check under the row cover regularly for beetles, and kill any that you find. This will work best in smaller gardens. Be aware that the insecticides listed (pyrethrum, pyrethrin, and carbaryl) are all toxic to bees. If you do choose to use them, apply them in a way to minimize bee exposure (for example, before the plants start to flower). Always read and follow pesticide label directions.

While larval feeding damage on roots can cause a problem, it is not something that has a remedy at this point. The best approach is to manage adult populations, which will lead to a reduction of egg-laying.

Yellow German IrisQ: When should I dig up and replant my irises?

A: Irises grow from thick, underground stems, called rhizomes, that store food produced by the leaves. Rhizomes grow slightly below the surface of the ground or at ground level. Many small roots penetrate the soil deeply. Every year, underground offshoots develop from the original rhizome. Offshoots may be divided and transplanted to grow new irises.

Irises should be divided 2 to 5 years after planting, when they become crowded. Divide and transplant irises in the late summer or early fall, after plants have bloomed. Cut leaves to one-third their full height. Dig under a clump of rhizomes and lift out the whole clump at once. Wash away soil with a steady stream of water.

Cut rhizomes apart with a sharp knife. Each division must have at least one growing point (or fan of leaves), a few inches of healthy rhizome, and a number of well developed roots. When separated from the original iris clump, each division is ready to plant.

variegated leaves

Q: I have a bumper crop of oak seedlings in my yard. About a half dozen of the seedlings have white or variegated green/white leaves. I have never seen this before, but wondered if there was a cause for this?

A: This is very interesting, and something I’ve never seen before. It looks like a genetic mutation. It would be very interesting to see how these seedlings progress; whether they continue to put our variegated leaves or eventually grow out of it and produce green leaves. Please keep an eye on them and stay in touch!

Clinopodium vulgare

Q: Would you tell me what this is?

A: The plant in the photo you have submitted is Clinopodium vulgare, wild basil. It is in the mint family, and is said to be native to Maine. See the following link for more information about the plant, Clinopodium vulgare.

Q: We’re not sure which of our two trees is Macintosh and which is Honey Crisp (both were potted when purchased and planted 2016). One has black spots on a few of its leaves. During June, it had only a few blooms followed by tiny apples, which fell off. After reading imfomation and looking at pictures, we’re thinking it might be scab. We are organic gardeners in southern Maine. What type of remedy would help this problem from spreading? I thought about taking all leaves with scab off right away.

Scab infection on an apple leaf.
Scab infection on an apple leaf.

A: Apple scab is recognized by the brown or olive green spots on leaves and the black spots on fruit. In severe cases, scab causes defoliation, which weakens the tree and inhibits flower formation. McIntosh, Cortland, and Macoun are very susceptible to scab. Removing the infected leaves, and keeping the area underneath the trees clean of debris will certainly help. See our Growing Fruit Trees in Maine website for more information on diseases of apple trees and how to manage them.

Since you just planted the trees last year, be sure to follow the guidelines for early establishment of fruit trees to keep them healthy.

You might find this fact sheet on apple scab disease from the University of Minnesota useful. Minnesota has a very similar climate to ours, so the recommendations are similar.

Q: What is your position on Bifen XTS 25.1% Bifenthrin Insecticide? Does it kill all bugs; i.e., beneficial insects, moths, and butterflies?

A: Bifenthrin is an effective broad spectrum insecticide/acaricide that can be used to control insect pests in the home landscape. It has also become the primary chemical option for the management of ticks. The use of pesticides such as bifenthrin can be an important component of an IPM program in combination with other management strategies including pest monitoring, cultivation, habitat modification, and bio-control. Since bifenthrin is a relatively broad spectrum product, it can kill a wide variety of insects and other arthropods, including beneficials such as bees, butterflies, and other pollinators. When using this product, care should be taken to limit pollinator mortality by spraying late in the day when bees are less active and avoiding spraying plants that are in bloom. Bifenthrin is also highly toxic to fish and aquatic invertebrates and thus should not be sprayed around surface waters. All pesticides, whether synthetic or organic have associated health and environmental risks. One must carefully weigh these risks against the threats posed by pests when deciding upon treatment options.

apples on treeQ: I have two older apple trees; one is a Wolf River. Every year the apples are useless because they are riddled with brown tracts and an occasional tiny whitish worm. We had the trees sprayed a few years ago with an orange spray, and then an insecticide-type spray the next year. Neither spraying improved the situation.

A: Older fruit trees do harbor a lot of insect pests and diseases. Two sprays over two years is simply not the proper pest management strategy. It takes real commitment to pruning, scouting for pests, identifying the pests and knowing their life cycles so you can apply the proper management techniques at the correct time.

Here is an excellent fact sheet on growing fruit trees in the home orchard that covers cultural practices as well as pest management, Growing Fruit Trees in Maine.

Q: Is it too late to plant an annual vine like Mandevilla?
A: It is too late (late June) to plant this annual tropical vine from seed or a small plant as it would not flower before frost hits. However, it is not too late to buy a nice one in a container from a local nursery.

Q: Is there any effective, non toxic method for squash bugs other then hand picking them?

A: When you say non toxic that implies no pesticides, not even organic as all pesticides are made to kill something and are thereby toxic. Having said that there are a couple of other cultural practices which can reduce populations other than hand picking including: laying out boards or pieces of newspapers where the insects will congregate. Turn over the boards and paper in the morning and scoop them up and put them into a can of water with a drop or two of dish soap to drown them.

The other strategy to reduce them includes cleaning the site up well in the fall to reduce overwintering sites.

Here are a couple of fact sheets on Squash Bugs:

Q: How much Epsom Salt do I add to one gallon of water for fertilizing tomato and pepper plants?

A: There is not much research based evidence that Epsom Salts are beneficial for vegetable production. Having said that there are a lot of home remedies that promote their use. There is some evidence that they can be beneficial in the late stages of growth for tomatoes and peppers, if they are showing signs of magnesium deficiency, which would manifest as yellowing between the veins of the leaves. A soil test would show whether your soil is deficient in magnesium. Contrary to popular belief Epsom salts do not help cure blossom end rot of tomatoes as that is caused by a calcium deficiency (epsom salts provide magnesium). Using a mulch such as black plastic, straw or grass clippings would keep the soil uniformly moist and that will help avoid blossom end rot if that is your concern. Here are links to some university based articles on the topic:

Asiatic bittersweet berriesQ: What is the best way to get rid of bittersweet?

A: Small patches can be hand-pulled. Take care to remove the entire root to prevent resprouting. Low patches have been successfully removed by cutting the vine and treating the regrowth with a triclopyr herbicide. Control is more successful in taller patches when cut stems are immediately painted with triclopyr or glyphosate. This plant has a substantial seedbank, and complete eradication may depend on repeating control methods for several years. For more information please read, Asiatic Bittersweet.

Q: We have dug up some of the plants that rooted around the rhododendron. How deep should we plant the piece that was underground? It was rather shallow.

Rhododendrons in bloomA: I assume you are talking about new shoots from the mother rhododendron plant? If so, you can dig them and place them where you would like to have the new plant. Plant it at the same depth it is now.

Q: I have some young cherry trees, I planted them bare root about 10 years ago. Some of them are developing a wilted and dying tendency on some of the branches. Is there anything I can do? Not all branches are affected at this point.

A: It is hard to say without getting a specimen to our Pest Management Office for diagnosis. However, here is a link to a fact sheet on cherry diseases.

Q: I planted my veggie garden and it is now infested with what appears to be teeny tiny mites of some sort they are climbing all over the sides of the raised beds they’re all through the dirt they’re everywhere would like to know what they are and how to get rid of them.

A: We will need either some very good digital images or a sample of these mites or insects to make an ID and any recommendations. Please follow the instructions here for the Insect and Plant Disease Diagnostic Lab, Submitting Insect Specimens.

Q: I have a tree that I believe was recently struck by lightening. It seems to be intact but has a long vertical break in the bark where the lightening apparently traveled. Much of the bark has been darkened. My concern is whether the tree is now in a weakened condition and possibly a threat to toppling over and causing possible property damage. Can you provide information about this or recommend a referral for assistance?

A: It’s difficult to say what the long-term effects might be from this lightning strike. Some trees go on to live long lives following a strike and others eventually succumb to this injury. Your tree is not in imminent danger of falling over, so I suggest a “wait and see” approach. If you notice symptoms like those described in this University of Florida publication, Lightning damages trees.  You should take steps to remove the tree. You can find licensed arborists at the Maine Department if Agriculture, Conservation and Forestry website.

Q: What source do you recommend for bird netting for fruit trees? I read that 1/4″ to 1/2″ openings are best. But I am only finding 5/8 to 3/4″. We have a cherry and a peach tree, as well as blueberries and concord grapes.

ripe peaches on treeA: I cannot recommend a specific vendor, but yes, the smaller the openings, the more successful you will be at preventing birds from taking your fruit. Since you have multiple plants to cover, it might be worth searching online as well as at local garden centers. A quick search yielded many results for me.

Q: We have a well that is about 350 feet deep. Most of our property is either exposed ledge or ledge just below the surface. We have some fields surrounded by ferns and wild blueberries. The fields were originally planted with grasses for cows and then horses. I mow them regularly but lately there is an abundance of nasty weeds that detract from the visual appearance of just grass. What kind of weed killer and what kind of fertilizer could I use on the fields? In the past, I’ve used the type of weed killer that is absorbed into the plant through its leaves and supposedly then kills the root, leaving no poison and harmful residue in the soil. That though is one weed at a time and is VERY time consuming. 

A: I do not recommend herbicides for homeowners. You mentioned you are on ledge, have a well nearby, and that this field is currently only for ornamental purposes. Herbicides should be reserved for instances where there is a health or safety risk, economic benefit, and used only after all other options have been exhausted. Something you might consider instead is converting this area to pollinator habitat. As you likely know, bee habitat is on the decline as are bee populations. How to Create a Bee-­Friendly Landscape is a great guide for how to get started. If you decide to go in this direction, you will also have the added benefit of less mowing! Using less fuel in your mower creates fewer emissions, costs you less, and gives you more time to enjoy our beautiful Maine summers. To maintain the open space, mowing or bush hogging once a season will keep tree saplings from getting established.

Plant or weed

Q: I have a plant that has come up in my flower garden this year and I am not sure if it is a weed. Please see photo.

A: I believe this plant is Narrow Leaf Plantain: Plantago lanceolata. This is a weed and has invasive tendencies. I would remove it and not let it go to seed. Here is a link to more photos and information.

Q: Our Plum tree has a growth on it. I’m afraid that it will spread to the green gage plum tree about 40 feet away or the apricot tree about 50 feet away. There are plums, pears, and apple trees even further away but in the same small orchard of about 20 trees. A walnut and hazel nut tree are within 40 feet. First question, how do I get rid of the infected plum tree without spreading the infection (or whatever it is)? I’m afraid when we cut it down it will spread spores, but leaving it isn’t good either. No other tree appears infected. Second question, what can we do to help the nut trees produce?

tree fungus
Black Knot of Plum and Cherry.

A: The growth you see on your plum trees is Black Knot of Plum and Cherry. I have listed some links to fact sheets on the disease, which include control strategies and pruning out and removing infected branches. It will spread to other plum or cherry trees but will not spread to nut trees. As far as helping your nut trees produce, I would follow general soil test results. Nut trees do take years to start producing.

Q: I have three high bush blueberry bushes that were pruned in March, I still have dead branches that need to be lopped off. Can I prune these branches now or mark them and cut them next spring?

A: Dead and broken branches can be removed (pruned out) at any time. The dead branches you see now most likely were winter killed and hard to spot when you pruned in March.

For more information on general care of highbush blueberries and pruning information please read this bulletin, Growing Highbush Blueberries.

Raised bed gardens
Photo by Tracey O’Connell

Q: I have a 24′ by 100′ raised bed vegetable garden. Is there any flower I can plant around the perimeter to keep pests (animal or insect) away?
A: There is no one flower that will deter both insects and animal pests. The best known deterrent plant is marigolds, which is unfortunately a bit of a myth. They do deter, and can be harmful to some soil-borne species of nematode plant pests, but there is no research to show they can deter other insects. In fact, marigolds may even attracts spider mites and snails.

Having said that, here are links to articles on companion planting from Illinois, Penn State, and Rutgers Cooperative Extension, which should help you decide what might be best for your garden bed area:

Q: Can you tell me why so many of the maple trees have batches of seeds on them this year? I have noticed that some have just seeds and no leaves but most have both. The two in my front yard are about 10 years old and this is the first year that they have batches of seeds along with leaves.
A: The red maple trees seed in the spring, while sugar maples seed in the fall. This does seem to be a heavy seed year for Red Maples so I think that is what you are seeing.

lilac with stressed flowers and leavesQ: We have several older lilac trees that are experiencing leaf curl and appear to have been chewed by some pest, although none are visible. The flowers have died halfway through their bloom. I did not prune much last year and was preparing to prune heavily this year but not sure the best way to help them recover. Is this blight?

A: Without physically looking at the plant, it is hard to make a diagnosis. That being said, you can send samples of leaves, flowers and other parts of the plant that are displaying symptoms, to our Insect and Plant Disease Diagnostic Lab – How to send a plant sample Pest Management lab in Orono. Our pathologist will take a look at the samples and contact you with his findings. There is no charge for this service.

You might also find this informational fact sheet from Penn State about common lilac diseases useful.

Lilacs are also susceptible to two insect pests lilac borer and oystershell scale.

Once lilacs are well established, pruning immediately after bloom can improve their vigor, appearance and future flowering. The goal of pruning is to maintain a clump of 7 to 10 stems of different ages. Cut a third of the oldest wood to the ground no more often than every 3 years. The oldest wood of lilacs is more susceptible to infestations of borers and scale insects. Also, thinning out vigorous top growth will increase flower bud formation by allowing sunlight to reach the center of the plant.

Q: Looking for someone to rototill an additional garden space at my home.

A: I would suggest checking your local yellow pages for gardening/landscaping companies.  If they are not able to do it, they may know of someone who does.
You may also wish to check out the Maine Landscape and Nursery Association list of landscape professionals.

Stewartia tree without many leaves
Stewartia tree without many leaves.

Q: Our stewartia tree in not leafing out this spring. Due to its location it may have been subjected to a lot of salt this winter. Do you have any suggestions for reviving this tree before we call an arborist? Mulch was applied within the past month.

A: Fortunately, Stewartia pseudocamellia (Japanese Stewartia) has no significant insect or disease problems. That being said, Stewartia is fussy about culture requirements. It is hardy to Zone 5 and performs best in part sun, preferably morning sun with shade from the hot afternoon sun, and evenly moist, well-drained acidic (pH 4.5 – 6.5) soil that has good organic matter content. Some leaf burn might be evident in drier summers (like we had last year) if the tree is in full sun.

Salt used for melting ice on pavements in during the winter can be quite harmful to trees. Salt damage occurs on plants when salt is deposited by spray from passing cars on stems and buds of deciduous woody plants. Salt spray can cause salt burn on buds, leaves and small twigs. Salt spray can also cause damage by desiccating the bud scales, exposing tender tissues of the developing leaves and flowers. The unprotected developing leaves and flower buds dry out and are often killed by the cold winter wind. Many times, the damage is not evident until late winter or spring. Needle or leaf browning, bud death, and branch dieback on the side of the plant facing the road or sidewalk is a common sign of salt spray damage. Damage to deciduous plants is not seen until growth resumes in the spring.

Plants are also affected by dissolved salts in runoff water. The dissolved sodium and chloride ions can displace other mineral nutrients in the soil. Plants then absorb the chlorine and sodium instead of needed plant nutrients which can lead to leaf burn and die-back.

Rock salt also causes damage when salt laden snow is plowed or shoveled onto lawns and garden beds. Salts in the soil can absorb water. This results in less water being available for uptake by the plants, increasing water stress and root dehydration.

Most of Maine had a lot of snow this winter and coupled with the drought we had last summer, your tree might be showing signs of stress from the two events. It wouldn’t hurt to have an arborist come over to check it out to see if the tree is still alive, or you could wait it out and see how the tree performs over the next few months into next spring.

Adult & nymph deer ticks
Adult and nymph deer ticks. Image by Griffin Dill.

Q: I live on the coast of Maine. At least two of our neighbors use “Talstar” insecticide outside to control, what they tell me are ONLY ticks and mosquitoes. I am researching the chemical and see that it is especially toxic to bees, among 75 different insect species, as well as aquatic life. Would you happen to have any more information? Are there restrictions by town? Do you know what towns prohibit this?

A: Pesticides can provide substantial benefits in, for example, maintaining public health and in managing pests in food production. However, as you are aware, they are a powerful tool that, if applied or handled incorrectly, can have unintended and sometimes harmful consequences.

Bifenthrin is the primary active ingredient in Talstar. This factsheet, National Pesticide Information Center highlights some of environmental concerns you already stated. It is important to note that these concerns can come about only when the pesticide is applied incorrectly. Each pesticide undergoes rigorous testing by the Environmental Protection Agency (EPA) before it is available to the general public. The information that comes out of that testing is contained in the label attached to each pesticide bottle sold. The label goes into detail about how to apply the pesticide correctly (rate of application, timing, weather conditions to avoid, set backs from sensitive environmental locations, safe storage conditions, and more) — so that those environmental concerns don’t happen.

Talstar is registered for sale in Maine. I am not aware of restrictions of its application by town. Pesticides need to be treated with great respect, but if handled, applied and stored properly can provide the intended benefit with minimal cost.

I commend you for seeking out more information! A suggested next step is to get the entire name of the product (there are 18 different registered formulations of Talstar in Maine alone!) — and look up the exact label for that product. It may help you to read the label in its entirety — to be fully aware of the potential environmental impact and to see the actions suggested, via the label instructions, to mitigate those potential risks.

broccoli in the gardenQ: We’ve had bad luck growing broccoli. Most years it bolts so if there are heads, they are very small. I feel we get the plants in the ground early enough and a lot of time we buy them already started. Could a certain nutrient be missing from our soil that could cause this to happen? Also, radishes don’t bulb up well even when thinned. Ears of corn are small. Legumes do well, as do peppers and tomatoes.

A: Sorry to hear you have struggled growing (or not growing) various vegetables in your garden. I would first make sure you are using Vegetable Varieties for Maine Gardens that are recommended for our Maine climate. Using varieties not adapted to our climate can lead to bolting (tied to day length and heat) and unproductive plants.

How to Prevent Cool Season Crops from Bolting has a good description on why plants bolt and how to manage it. It is important to note that the longer days of summer triggers bolting. You may have better success by planting broccoli towards early July for a Fall harvest (the days are getting shorter).

Growing broccoli, cabbage and cauliflower in Minnesota has a good overview on growing broccoli and other cole crops.

You may also wish to test your soil and make sure that the plants have the nutrients they need and correct pH to grow well.

Keep an eye out for pests and diseases. If you see anything that looks suspicious, bring it to your local Extension office for identification. The sooner you identify and address any pest problems, the easier they are to manage.

Gardens need full, direct sun as well, so make sure they are sited in a good location.

Q: Can I plant corn with Lumite Ground Cover? Would I burn a long continuous hole in the fabric for the seeds?

A: Lumite is okay to plant with edible crops. For corn placement, you can burn individual holes with a blow torch. The torch will cut and melt the edges so the weave doesn’t come unwoven. This is okay but creates holes in your fabric, and doesn’t allow you to easily adjust for crops with different spacing without making more holes (and more spaces for weeds to pop up through).

Alternatively, you can use the 3-foot-wide rolls of Lumite, leaving a gap in between when you place the rolls down. You plant the corn in that gap space; i.e., you place a 3-foot strip on the outside, then a row of corn, then another 3-foot-wide strip in the middle, then another row of corn, etc.

Q: We have tried to grow bell peppers in zone 4 with no success. Any suggestions would be greatly appreciated.

A: Sorry to hear you have struggled growing (or not growing) bell peppers in zone 4. For Maine’s climate please read, Vegetable Varieties for Maine Gardens.

In Evaluations of Sweet Pepper Varieties you will find trial results for different sweet peppers grown in Maine.

Here’s a good overview on how to grow strong pepper seedlings for transplant.

Also be sure to test your soil to ensure that the plants have the nutrients they need and correct pH to grow well.

Keep an eye out for pests and diseases. If you see anything that looks suspicious, bring it to your local Extension office. The sooner you identify and address any pest problems, the easier they are to manage.

Peppers need full, direct sun as well, so make sure they are sited in a good location.

Q: Do you have a frost date map for Washington County?

A: Freeze/Frost Occurrence Data (PDF) can help you determine frost-free dates for locations throughout Maine. You can also look up your first and last freeze/frost dates by zip code. Our Plant Hardiness Zone Map of Maine includes additional information.

Q: I have a number of morella pensylvanica northern bayberry shrubs in my yard. How would I go about propagating them from woody stem cuttings?

A: The best way to propagate would be from softwood cuttings. For more information on propagating from both softwood and hardwood cuttings, see Propagation of Woody Ornamentals by Cuttings (PDF) and Propagation of Shrubs from Softwood Cutting. Also note that barberry is suckering in its habit. Shoots with roots can be separated from around the bases of the parent plants and planted elsewhere.

Highbush blueberry branches
The green shoots are last summer’s growth. The gray branches are older growth that are part of the cane. The longer, thicker shoots on the left of the photo (8-10”) should be saved. The weaker shorter shoots on the right should be trimmed off.

Q: Some of my high bush blueberry bushes are just dead wood. They were fine last fall. What might be the problem? They were not fertilized after July.

A: We had a hard winter and it sounds as though your blueberry bushes have winter dieback. Highbush blueberries push the edge of their adaptability to Northern New England temperatures and so it is not uncommon for them to get injured and die back during a harsh winter. As a quick aside, I have had to prune some of my established ornamental shrubs back hard this spring because they had a lot of dieback this winter. Thankfully, the heart of the shrubs, closer to the ground and buried under some leaves, survived! Highbush blueberries are not related to my shrubs, I added that in just because it was an indicator to me on how hard this winter was on some of our plants.

See Growing Highbush Blueberries for information about pruning out the damaged wood. Hopefully, part of your plant survived and will regrow. Depending on how much damage there was and how old the blueberry bushes are, it may take a few years before the blueberry is back to its size last fall.

Going forward, you may want to see how you can protect your blueberries during the winter. For example, consider relocating to a more protected site.

late blight on tomatoes
Tomato plants infected with late blight.

Q: What can I plant in my raised beds that had tomatoes that suffered blight last year? I removed and disposed of the plants the best I could. I was considering peas and/or beets, but would greatly appreciate suggestions.

A: Your question is a bit difficult to answer in that I am not exactly sure what you mean by blight — early blight, late blight, septoria leaf spot? “Blight” is often used to describe several different, completely unrelated, plant diseases.

I will take a guess that perhaps you were struggling with early blight. UMaine Extension’s bulletin #5087 Early Blight of Tomato and University of Minnesota’s Early blight of tomato include pictures of what the disease looks like and how to manage it.

In short, anything NOT in the solanaceae family can be planted in those raised beds. The solanaceae family includes potatoes, tomatoes, peppers, and eggplants — so avoid these in the raised bed and all other crops are fair game. Vegetable Varieties for Maine Gardeners includes a list of crop varieties suited to Maine.

Keep in mind that early blight is a fungus and can overwinter in the soil and crop residue. I would encourage you to plant early blight resistant solanaceous crops in the rest of your garden area to avoid/minimize damage by any early blight spores that have carried over the winter.

The publications cited above have additional management techniques.

If, after looking at the pictures, you determine that your tomatoes did not have early blight last year, please drop us another line — along with photos, if you have them — so that we can identify the disease you struggled with. Proper identification will help us give you the best information on how to control the disease going forward.

Q: How far away from the leach field should vegetables be planted? Would a raised bed within ten feet be safe?

A: Ten feet may not be a safe distance from the absolute edge of your leach field, especially if it’s an older system or you don’t know where the exact boundaries are. For more information, see our fact sheet Vegetable Gardens & Septic Systems Don’t Mix.

Comparison of 2 common types of white grubs in Maine: European Chafer grub (on left) is larger than the Japanese Beetle grub (on right). Photo by G. M. Dill.Q: My yard is plagued with grubs (2nd year in a row). We have treated with grubex (multiple times before forecasted rain) but nothing is working. Large sections of our yard have dead grass and the skunks are having a feast every night eating the grubs. Are there any other options to get rid of grubs in our yard?

A: I would encourage you to give GrubEx, or another pesticide, another try. The way to control grub damage is to kill the larvae (although I know it’s hard to wait to do that as the adult grubs/skunks are tearing up your lawn right now).

GrubEx is an effective product, but it controls the eggs and must be applied 60-90 days before the eggs are laid in July. This means that application(s) should occur in April (so ASAP). The product label (GrubExSeasonLongGrubKiller (PDF)) said it provides 4 months of control. So, if you apply in April, give it 60-90 days to take hold (June to July) — you’ll be covered for this summer (June – September).

Making sure the product is applied 60-90 days before the eggs are laid is important because it takes time for GrubEx to work itself into the roots of the turf so that when the larvae feed on the roots they consume the GrubEx as well and die.

Please read this publication carefully: Grubs Got Your Lawn? (PDF). It is chock full of great information — i.e. how the pesticides work, egg laying dates, the alternative use of water to control grubs, how to repair lawns with grub damage, etc. NOTE: Please use the water method or the pesticide. Do not apply the pesticide and then water consistently — you will wash away the pesticide.

Goutweed
Goutweed (Aegopodium podagraria); photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Q: My raised beds a full of Bishop’s Pie Weed. How do I get rid of it? The plants break apart when I try to dig them out. The bits stay in the soil and seem to regenerate!

A: Bishops Weed, Goutweed, or Aegopodium podograria, is one of the most aggressive plants in the garden. (The variegated one is called Snow-on-the Mountain.) Most people have a very hard time getting rid of it because it’s in and around the stems and roots of other desired plants. It’s one of the plants that can hitch-hike on home-dug specimens, unfortunately making gardeners cautious of plant sales.

Goutweed is on the invasive plant list in many states. It is finally listed in Maine. Here’s the fact sheet about goutweed we often send to clients. It lists different mechanical and physical control methods, which should always be tried before chemical controls.

When using chemical controls, always follow label instructions.

Translocated herbicides are not effective in the spring, when energy is flowing UP from the roots to the leaves. They work only when the plant is photosynthesizing completely (after June 10 and into early fall) and all energy is going DOWN from the leaves to the roots, translocating the poison with it. If you tire the plants out first (cut, pull, weed whack), the herbicide will be even more effective. The same applies to poison ivy and other plants with perennial roots.

Covering the whole area with black plastic can further weaken the colony. (This can only be done in a large clear area of course.) After the plastic comes off in late August, weed whack, allow it to re-sprout, and then hit it with an herbicide once it’s an inch tall.

Be very careful when digging or sifting the roots. The goutweed can then colonize a compost pile or other are where the material is discarded.

garlicQ: I did not harvest my garlic last fall. The bulbs are all sprouting now. Can I successfully break them apart and replant at this point?

A: In short, yes, divide and replant ASAP. You can find additional information on planting and caring for garlic in Maine at Growing Hardneck Garlic in Your Maine Garden.

Q: We have built three, 5’x10’x10″ raised garden beds, and are now trying to figure out the appropriate soil mixture for optimum growth for our vegetables. I have read that a good combination is 50% compost, 25% sphagnum peat moss, and 25% sand. Does this seem okay to you? In using sand, what type of sand should I be using?

Raised beds by Dennis ConnellyA: For raised beds, we suggest a mix of 75% screened loam and 25% finished commercial compost (not composted manure). Many compost suppliers and nurseries deliver this kind of “gardener’s mix” by the yard. (Some mixes are 50% loam, 50% compost, which is okay.) Peat moss will work for part of the organic matter component, but it’s very expensive, tends to repel water, is mined from a finite resource, and provides very few nutrients.

Once you fill the beds, it might be wise to test your soil. Your soil test results will come back with nutrient readings so you will know what you might need to add during the growing season and also whether you need lime or sulfur to raise or lower the pH. You can pick up soil test kits at any county Extension office. We can also mail one to you.

This soil volume calculator can help you find what you need to order.

Information about raised bed gardening can be found at Gardening in Small Places.

Visit our website for information about an upcoming raised bed gardening program in Springvale.

septic leach fieldQ: What is a safe distance to plant from a leach field? The area is gently sloped for about 25′ then there’s kind of a mound parallel to the length of the leach field. Behind it a seasonal wetland that drains to a salt water cove.

A: Please see Bulletin #2442 Vegetable Gardens & Septic Fields Don’t Mix for detailed information about planting near leach fields.

Q: If there is a large vertical space between sets of branches (whorl?) in a spruce tree can the tree be made fuller by pruning the existing branch ends?

A: In response to your question, please do not prune the existing branch ends – this is called shearing and contributes to the overall decline of evergreens when done consistently. Shearing can provide a flush of ‘filling in’ but is not a long-term solution. If the tree has reached the height you would like it to be, removing the central leader promotes internal branching and greater density in the tree – giving you the fuller look you desire. This technique works best if you remove the leader just as the tree has reached its ideal height and still has ‘young tissue’. If the spruce has developed old wood, and depending on how old this Spruce is, that may not work. Older wood does not have active buds that would emerge and grow upon pruning.

Please take the time to read and process both of these resources, Pruning Evergreens in the Landscape (PDF) and Pruning Woody Landscape Plants.

As a general rule, prune evergreens with more caution and less drastic cuts than you would apply to deciduous plants, due to evergreen’s slower growing nature. Light, periodic pruning — over several years — may be needed to remedy this empty space in the tree.

poorly formed raspberries on the vineQ: We have an issue with raspberries. We get fruit, but for several years many of the berries are not complete. The attached photo is typical. Is this just a lack of pollination? Could this be related to soil acidity or nutrients?

A: It is due to lack of sufficient pollination. Here’s a good article about it, The Importance of Pollinators. The article also gives information on how to cultivate more native bees and bumblebees (excellent pollinators of raspberries).

Q: I am looking for recommendations for landscape trees in front on my recently-built home. We are looking for a single trunk with lacy see-through foliage (not wanting to block the home views) and hopefully slow growing. The current trees fit the bill aesthetically — Himalayan Birch — however, they have a borer disease as diagnosed by a tree specialist. I am willing to try again with the same type of tree, but want to explore other options, too, and am looking for recommendations for this unique location. I also plan on installing an irrigation system this spring to counter the summer dryness. The planting bed around the trees is mulched.

A: I think you’ll find our bulletin about Maine’s native plants helpful. It gives a plant list with light and moisture requirements, expected height, and comments about conditions in which the plant grows. You’ll need to scroll down a bit to reach the plant list, which starts off with trees but also includes shrubs, ferns, flowering plants, etc. Our bulletin about nurseries and garden centers offers resources on native plants (wholesale and retail).

When considering a new tree for my landscape, it’s helpful to see the plant in person before settling on anything. Scan the native plant list for some possibilities given your conditions, and then head to a local nursery to view them. Individual tastes can vary so much that it’s important to view the plants in person to select what you like.

late blight on tomatoes
Tomato plants infected with late blight.

Q: I’ve been dealing with early blight the last few years, resulting in a very low output of tomatoes. My four raised beds are in close proximity to one another. A local master gardener recently told me I should forget about trying to grow tomatoes for three years in these beds. I assume this will enable the fungi (or spores) to dissipate. Does this sound right? Can I try to grow tomatoes elsewhere in my backyard? If I use a new raised bed, how far from the blight-infested beds would it have to be placed? Is there anything I could do to the soil in the beds to help eradicate the early blight? Lastly, should I get rid of the metal cages I’ve been using, thinking the fungi may be on the exterior of the cages? Should I wipe the cages down with bleach perhaps?

A: See Early Blight of Tomato for an overview of how Early Blight spreads and how to manage it. Another excellent article that highlights some additional information is management and resistant cultivates.

To get a bit more into the weeds, disease management is about removing at least one element from the disease triangle, so that the disease doesn’t take hold. All three aspects (susceptible host, pathogen, and conducive environment) must be present for the disease to get established. In many cases, all three aspects must be present AND for a certain length of time.

This may help you understand better the disease management instructions given at the Early Blight links above. Those management practices are ways to reduce/eliminate at least one element from the disease triangle. Your best bet would be to implement several of the management practices at once. I would recommend, at least:

  • using crop rotation (not planting tomatoes or potatoes in those raised beds for 3 years),
  • cleaning up any leftover crop residue at the end of the season
  • conduct a soil test and follow its recommendations. Remember that too many nutrients can be detrimental to the plant and the environment, so please test
  • keep plants well watered – and mulched
  • and, if you wish to plant tomatoes elsewhere in your garden – select resistant varieties. Since it is a fungus and travels readily by air, you won’t be able to plant your plants far enough away to not have the spores reach them.

Resistant cultivars
There are many resistant tomato cultivars available, often designated with an “EB” in seed catalogs. There is also an extensive list of resistant cultivars on Cornell University’s vegetable pathology website. Resistant varieties are not immune to early blight. Rather moderate levels of resistance to either leaf infection, stem infection or both are present.

A few common cultivars with early blight resistance include:

  • Iron Lady
  • Mountain Supreme
  • Mountain Magic
  • Defiant PhR
  • Jasper
  • Juliet
  • Verona

You don’t need to get rid of the metal cages you have, but I would sanitize them with bleach.

rows of lettuce plants; photo by Edwin RemsbergQ: What variety of lettuce is the most heat tolerant? My grandson would like to grow lettuce in Jamaica but the hot weather may cause plants to bolt.

A: Your best bet is to reach out to one of the nearest Cooperative Extension offices in either Puerto Rico or the US Virgin Islands to see what they suggest.

Since lettuce is a cool season crop, you may have to try and grow it only during your cooler months of the year. Other techniques would be to use some shade and mulch the garden soil to try and keep it moist and cool.

Q: Would you give me approximate time to start seed plants so they are ready to go into my garden?

tomato seedlingsA: The timing of when you start seeds indoors will depend on the type of crop you are growing and the frost free date for your area. Enter your zip code on this website to determine an estimated frost free date for your region and use Johnny’s Seed Starting Calculator to determine when to start a variety of crops. For more information, see Bulletin #2751, Starting Seeds at Home.

For central Maine gardeners, here are some crops you’ll want to consider starting soon:

Late March: hollyhock, snapdragon, stock, artichoke, kohlrabi
Early April: pepper, eggplant, broccoli, cauliflower, cabbage, beets*, coleus, status, impatiens, larkspur, cosmos, sweet pea*
Mid April: lettuce*, calendula, marigold, tomato, basil
Late April: chard*
Early May: cucumber*, melons*, sunflower*, morning glory*, zinnia, squash*, pumpkin*
Mid May: broccoli**, Brussels sprouts**, cabbage**, cauliflower**

* usually direct sown, but may be started indoors
** for a fall crop

Q: My two 7-year-old plum trees are growing vigorously, but I haven’t been able to harvest any plums. Each spring there are plentiful blossoms followed by lots of tiny growing plums, but they don’t seem to get much bigger than an olive before they drop off the branch. Any idea why?

A: Possible causes of premature fruit drop in plums include:
  • Plum curculio damage. See images and management options here.
  • Insufficient moisture or underdeveloped root system. Solutions include irrigation, mulching, and thinning fruit crop before it develops.
  • Flowers not fully fertilized. Identify what variety of plum you have, check out this piece on pollination requirements, and reconnect with us if you need help determining whether it needs another pollen source.
More information on planting, early care, pruning, insect/disease management and more can be found on our Growing Fruit Trees in Maine website.

Q: Looking for some help on growing vegetables hydroponically. Are there any classes or anything that would help me with that?

A: I don’t know of any workshops being offered by Extension in the near future, but I encourage you to reach out directly to your local county extension office to see if they know of any community partners who might be holding a workshop in your area.

Here are a few helpful resources on the topic:

Don’t hesitate to reach out to your local office if you have any further questions.

sowing seeds in pots
© Lisa Looke, Photos courtesy of Wild Seed Project

Q: When is the best time to start growing seeds indoors? What time of year is the last frost? Do I also need to start lettuce and spinach indoors?

A: To find the right time to start seedlings for your region, work backward from the average last frost date. Go to the following website where you can hover your cursor over your town. This will give you the average last spring frost date. (Just to be clear, there is STILL a 50% chance that a frost will occur after that date, so be careful and protect your fragile seedlings)!

Seed Starting contains information on when to start seeds based on when you want to set seedlings out in the garden. Your seed packets will have more information on the back about the number of weeks before transplanting to start a particular vegetable.

Spinach and lettuce seeds can be sown directly in the ground, or started ahead of time as seedlings. They are tolerant of cooler temperatures, and can be put in the ground three to four weeks before your average last frost date, as long as your soil has thawed and drained its excess water.

For frost-sensitive (warm season) crops such as tomatoes, peppers, cucumbers, squash, beans, and corn, wait to set them out until ALL danger of frost has passed. That could be as early as your “average last frost date,” but watch them closely and prepare to cover them if a frost is predicted or, to be safe, wait until Memorial Day. For pepper plants, wait until the second week June before setting them out. They are very sensitive to temperatures below 50 degrees Fahrenheit.

Q: I’m originally from Kentucky and I’m finding it hard to find mustard greens in the Augusta area. Can I grow them in my Maine garden? Is there a particular variety that you recommend?

A: There are several different types of mustard greens that can easily be grown in your Maine garden. They are a cool season crop, and can be directly seeded in your garden as soon as the soil can be worked in the spring. Because our summers remain relatively cool, mustards can be grown in succession plantings through the entire growing season into the fall. Here is a link to a bulletin from Utah State Cooperative Extension on growing Mustard in the Garden (PDF).

Here are links to Maine-based seed companies from whom you can order a variety of mustard seeds:

Q: We filled in an in-ground swimming pool with sand last year. We now want to use that area for gardening. What type of soil and how deep would it need to be to grow vegetables? (We know we’ll have to take out some of the sand but hopefully not too much, especially in the deep end.)

woman weeding vegetable garden; photo by Edwin RemsbergA: I suggest you replace the sand with 18″ to 24″ of screened garden loam mixed with compost. This can often be purchased by the cubic yard from a local nursery or landscaping business, which is much cheaper than buying it in bags. If you are growing vegetables, make sure the loam is not mixed with composted municipal solid waste. It would be a good idea to have a soil test done on the loam before you start gardening in it, so you know what you are working with and whether or not it needs amending to adjust the pH or nutrient levels. Please realize that where the loam meets the sand beneath it, due to a change in soil texture, water drainage will slow down. It is best not to have a dramatically different horizontal layers in the soil, so if you can “feather” some of the loam into the underlying layer of sand where the two meet, it would ensure better drainage.

Q: I just purchased a greenhouse and am wondering how soon I can put seedlings in it? It will be unheated and is approximately 6 feet by 8 feet. I live in Rockport. I plan on starting seeds inside my home and then move the seedlings to the greenhouse when it’s warm enough.

Also, I grew kale from June to October last year and in September I noticed that aphids and the green cabbage/broccoli worms were starting to show up in large numbers on the kale. Is there anything I can do to the soil before planting to help prevent them coming back?

A: Seedlings of cool season crops (kale, cabbage, etc.) can go into an unheated structure in early- to mid-April. Warm season crops (tomatoes, peppers, melons, cucumbers, etc.) can go in late April to early May. In both cases, daytime temperatures inside the greenhouse will need to be closely monitored, especially on sunny days. Daytime temperatures can easily reach dangerously high levels if the house is not vented. Seed germination can be hastened by use of a root zone heating mat. This will also allow earlier starting of seedlings as the root zone heat will protect plants early in the season.

There are no effective soil treatments for aphids and cabbage worms. Cabbage worms can be managed by using light-weight row covers to prevent adults from laying eggs on the plants. Routine scouting for both pests can be used to effectively time your control measures.

Q: Can I legally grow currants in Sangerville, Maine?

White pine infected with White Pine Blister RustA: It is illegal to possess, transport or sell Ribes plants (currants and gooseberries) in most areas of Maine, including Sangerville. White Pine Blister Rust (WPBR) is a serious disease of white pine, a major forest and economic species in Maine. This disease weakens and kills infected trees and can prevent the regeneration of white pine in some forest areas. Ribes species play an important role in the survival and spread of the disease. Infections of WPBR cannot be passed from pine tree to pine tree, but must infect a Ribes plant to spread to pine. See Towns Regulated by Maine’s White Pine Blister Rust Quarantine (PDF) for a map and a complete list of Maine towns.

For more information on State forestry related quarantines in effect in Maine, visit Quarantine Information.

Q: Last year I planted two nut-bearing walnut trees. I don’t recall if they were either English or Carpathian. I just learned that black walnuts have a natural poison which effects many plants nearby. Are other walnut varieties as toxic as the black? Mine are not near the vegetable garden, but I was hoping for a flower garden nearby. Also is the spacing of 20 feet correct?

walnuts ripening on tree
Photo courtesy: Robert Vidéki, Doronicum Kft., Bugwood.org

A: English and Carpathian walnut can reach 40′ to 60′ in height with a comparable or greater spread at maturity, so your 20 foot spacing is a little tight. In the long run, if you do not want their canopies to overlap at maturity, they would be better off spaced 30 feet apart. For more information on Carpathian walnut, which is a variety of English walnut, see this fact sheet from the University of Idaho (PDF).

They do produce the allelopathic chemical juglans, but not in the same concentration that the black walnut produces. Highest levels are in the root system and in the nut hulls. See the following links for more information, and suggested lists of plants that are resistant to juglone:

Q: We’re having issues with our kale; it’s showing leaf scorch on its apical meristems. We have green curly kale varieties (mostly Winterbor, Darkibor, and Starbor) as a winter harvest crop in our unheated high tunnels. They were planted back in September and were mature when we began harvesting them in late December. Our kale has been under high hoops with three layers of Agribon floating row cover. Layers have been removed or plants uncovered as needed based on fluctuating temperatures and cloud cover. Despite our monitoring and considerations in management, the majority of our green curly kale plants, especially those planted on the southern end of the high tunnel, have suffered weakening of stems/leaf veins and browning/necrosis of leaf tips and of those new leaves emerging from the meristem. We’re wondering if it’s the fluctuating temperatures or extremes that we might not be anticipating in our management of the tunnels. What could be causing this leaf burn?

A: Fluctuating temperatures could and would be a cause of leaf burn along the margins at this time of year. Though Kale is a very hardy green, it is not as hardy to the extreme cold temperatures we get in mid-winter as spinach would be. The cold won’t kill it but can burn the margins which would make it less valuable to market. The good news is as we get into February and the days start to lengthen there will be a lot of new growth that should be a nice lush dark green without the leaf burn. You could cut the kale back and let it come up clean since we are now getting into the longer days.

I have grown kale myself in a winter greens small moveable greenhouse and have experienced the same thing. A couple of nights on 5-10 degrees below 0 is enough to cause leaf burn. I have tried a lot of different winter greens and by far the most hardy and resistant to burning is spinach. You just can’t kill it. For mid-winter in an unheated high tunnel spinach could be a more marketable winter crop, with kale planted for late fall and late winter harvests knowing that you may still experience some leaf burn in mid-winter.

You could also send specimens to our Insect and Plant Disease Diagnostic Lab at 491 College Avenue, Orono, ME 04473 for analysis, to make sure it is indeed an environmental cause (extreme low temps) causing your problem and not a disease.

Q: I live in the lower part of Washington County along the coast. What’s the right time to start vegetables indoors for spring transplanting? What vegetables would your recommend for this?

seedlings on indoor growing racks
Photo by Joe Bergeron.

A: To find the right time for your region, work backward from the average last frost date, which for you would be approximately May 14th. For frost-tolerant (cold hardy) crops like lettuce, peas, carrots, spinach, and kale you can subtract 3-4 weeks and set those seedlings out as early as late April/early May. For frost-susceptible (warm season) crops such as tomatoes, peppers, cucumbers, squash, beans, and corn, wait to set them out until danger of frost has passed. That could be as early as May 14 if you watch them closely and prepare to cover them if a frost is expected or, to be safe, wait until Memorial Day.

Seed Starting contains information on when to start seeds based on when you want to set seedlings out in the garden. Your seed packets will have more information on the back about the number of weeks before transplanting to start a particular vegetable.

As to what to grow, the choices are unlimited and really depend on what you like to eat. There are recommendations in Vegetable Varieties for Maine. If you check seed catalogs, there are many more varieties and crops you could choose from and more varieties are added every year. Using a Maine Seed Catalog like Johnny’s Select Seed, Pinetree Seeds, or Fedco Seeds would ensure you get the right varieties for Maine.

green tomatoes on the vine; photo by Edwin RemsbergQ: What is the best time to plant tomatoes in Boothbay Harbor?

A: The frost-free dates for Bar Harbor (closest I could find to Boothbay Harbor) are May 17 to October 3.  Since tomatoes are a warm season crop, you should definitely wait until after May 17 to plant your tomato plants. You may want to wait until Memorial weekend to be sure or look at the 10-day forecast for your area to see what risks you might be facing in a particular year if you plant that early and be prepared to cover the plants if the temperature dips unexpectedly.

Q: I have a flowering tree, maybe a type of dogwood, that has grown through my rock wall along the stream beside my home. It is slowly dying and I would like to save it or, if needed replace it for the shade and retaining qualities for the rock wall see photos I would appreciate any thoughts.

trees growing along a streamA: It is hard to tell from the pictures what might be wrong with the tree. The big tree looks pretty healthy and also looks like a maple tree. The smaller tree is hard to identify from the pictures. Trees can suffer from a number of issues: drought or too much water, lack of fertilizer, too much fertilizer, lawn fertilizer that contains an herbicide, lawnmower damage, late spring frosts, and even old age.  Any of these causes might be having an impact on tree health. If you can discover the cause, you may be able to address the cause and preserve the health of the tree. If not, as in the case of old age, you may need to replace the tree with another option. Some trees that would do well in Maine include the natives Alnus rugosa or speckled alder in wet sites, Amelanchier arborea — Juneberry, Amelanchier laevis — Allegheny serviceberry, Hamamelis virginiana — common witchhazel, and Cornus alternifolia — pagoda dogwood.

blueberries on bushQ: My blueberry bushes have not bloomed yet. How long does it take?

A: Your blueberry bushes should start blooming right away, assuming you purchased them as a 1-3 year old plant. Usually, it is recommended you pick off the blossoms the first couple of years. They may not have bloomed if the soil pH was not right or they didn’t get enough sun. For more information, see Growing Highbush Blueberries.

Q: Last year, I grew a small variety of heirloom and hybrid tomatoes. My husband and I also grew several potato varieties as well. I was just wondering if you had any suggestions to increase our yield for 2017 with a new tomato variety. For tomatoes, we grew: Cherokee Purple, Big Zac, Rapunzel, Azoychka, Abe Lincoln, Carmello, and a few more. The only varieties that produced well for me were: Big Zac, Carmello, and Rapunzel. I did save my Carmello seeds and I will be planting them again this year, but I was wondering if there were any high producers that were heirloom tomato varieties that you would recommend? Last year, we also grew Yukon Gold, Magic Molly’s, and White Kennebecs for potatoes. Is there an early potato heavy producer that you would recommend?

vine ripening tomatoesA: It looks like you are growing a great variety of tomatoes. If you like heirloom tomatoes and cherry tomatoes in particular, I would suggest Matt’s Wild, which is a very prolific producer. I would also suggest Juliet, which is not an heirloom but a very reliable producer in all sorts of conditions. For potatoes, Caribe, and Red Norlands are reliable early season varieties.


Questions & Answers from 2016

Questions & Answers from 2015

Questions & Answers from Previous Seasons