Ask Our Garden Experts: Questions and Answers from 2016

If you have a gardening question, you are welcome to

Questions and Answers from 2016

Answers to this season’s gardening questions are provided by Tori Jackson, Extension Educator: Agriculture and Natural Resources, UMaine Extension Androscoggin & Sagadahoc Counties; Donna Coffin, Extension Educator, UMaine Extension Piscataquis & Penobscot Counties; Kate Garland, Horticultural Professional, UMaine Extension Penobscot County; and Frank Wertheim, Extension Educator, Agriculture/Horticulture, UMaine Extension York County.

greenhouse in snow
Four-season structure in mid-winter.

Q: We have a greenhouse we recently built ourselves. I was wondering if there has been success in planting seedlings this time of year and successfully growing greens, or maybe what might grow through the cold months. Is container planting recommended or more garden beds in the greenhouse? Is heat necessary to germinate and keep the plants growing or will they take without a heat source? Should we consider passive solar resources and are you aware of any grants currently available for Maine residents? What about using agricloth at night to keep plants insulated? Thanks for any assistance.

A: A true greenhouse is a heated structure with permanent walls and benches where plants are grown in containers. A hoop house is a less permanent structure, covered in plastic that can be rolled up and is meant to cover the soil beneath it. If you have a greenhouse, you generally use flats and containers as well as supplemental light and heat to start plants early in the season, and (if you can afford the heat and electricity), to grow some things year-round, like greens. Hoop houses can also support winter growing, though most things are generally planted well ahead of this time of year, because of the light required for most plants to germinate. Row covers are often used in a hoop house to provide an extra layer of protection on cold nights. There may be some incentives for solar, but there are no grants for homeowners available for this kind of thing. Check out Growing Winter Greens form Penn State, and Bulletin #1022, Maine Season Extension Options: Making the Right Choice for Your Farm for more ideas about how to grow year-round in your new structure.

Q: I want to dig up my red and white geraniums and winterize them for next spring’s planting. What do I cut them down to? What soil, water, and light conditions do I follow? They will be stored in a heated garage.

A: A fact sheet Overwintering Geraniums from Iowa State Extension does a nice job of explaining how to overwinter them.

garlic; photo by Edwin RemsbergQ: I planted my garlic 28th of September. We just returned home to find them up 2- 1/2 inches. Can I put more leaves on top or do I have to pull up the garlic and replant it? I planted 300 cloves.

A: It’s always a gamble to plant garlic in September when it is so pleasant to be in the garden, and we have had some warm days since September 28th. Luckily, garlic is very hardy and will likely not be damaged by this late fall growth. Mulch your plants heavily with straw to limit light, keep moisture in, and insulate your planting to protect it from too much thawing once it freezes for the winter. For more information on growing garlic, check out our garlic page.

Q: What is the best way to overwinter my Concord and table grape vines? Also how and when should I prune them?

Edelweiss grapes on the vine
Photo by David Handley.

A: Small Fruit and Vegetable Specialist David Handley’s comprehensive guide Growing Grapes in Maine should answer all of your questions.

Q: Bumblebees pollinate my garden. They have disappeared this year. Some other smaller bees did pollination, but poorly. How do I get the bumblebees back?

A: There are a number of things you can do to make your yard more pollinator-friendly. Our factsheet “Understanding Native Bees, the Great Pollinators: Enhancing Their Habitat in Maine has a great section on how to make your yard more “Native Bee” friendly.

Q: I impulsively bought two highbush blueberry plants that I plan to naturalize into my landscape here in Newfield, Maine. I’m realizing now that I need to amend soil a bit as well as learning (through your site) that planting in early Spring is the best option. Can I simply place the well establish/leaved 2- to 3-year nursery plants in their containers outside away from winds for the winter?

A: You are wise to wait until the final planting site can be properly amended before planting. Your best bet is to remove them from their pots and temporarily sink them into the ground in a holding area for the winter. The soil will help protect them from freeze/thaw cycles that can damage the roots. Water and mulch well before the ground freezes solid. Some good mulch options for this situation include leaves, straw, bark mulch, or wood chips.

Q: I have never used fertilizer spikes. Do you recommend them? I would like to fertilize my old apple trees, and I wondered which fertilizer spike is best?

Aapples on tree: Fall is not the time to be fertilizing fruit trees since they won’t go into dormancy as well as they should.

Also, fertilizer is less important than pruning when it comes to revitalizing old apple trees. Pruning is done in the spring and fertilizing can be done before July 15.

I use granular fertilizer that can be evenly spread around the drip line of the tree. The spikes will only provide nutrients in the small area where they are driven in the ground. It’s hard to say what analysis of fertilizer you need without a soil test. Maine soils are also on the acid side so you may need lime more than the other nutrients. We do have a fact sheet “Renovating Old Apple Trees” that also discusses pruning, soil testing and the application of nitrogen.

Q: I have pruned some old apple trees in a field. Should I seal the little cut circle edges


espaliered apple trees
Espaliered apple trees form a thematically perfect wall at the edge of the garden.

with paint? I don’t want to buy a wound product, but I do have some green water-based house paint. Should I let nature take its course or attempt to coat the raw edge?


A: It’s best to leave the tree unpainted. Here’s an excerpt from our bulletin Pruning Woody Landscape Plants: “Tree paints and wound dressings should rarely, if ever, be used by a homeowner. Recent research has shown that these materials are rarely beneficial. In fact, they may sometimes prevent plants from successfully compartmentalizing wounds. Sometimes arborist use wound dressings if they are pruning at a time of year when a specific insect or disease organism is active.”

Q: I have about 18 Amish paste tomato plants. They seem to be taking forever to ripen and the flavor is flat. They are dropping off the plant before they ripen or half ripened. I picked up about 2 dozen tomatoes from the ground. I have not had tomatoes drop off of a plant as much as this before. Also, the plants are healthy there is no blight or fungus on them.

A: The premature fruit drop you are observing is likely due to the dry growing season we’ve had this year. Many fruiting plants will abort flowers and developing fruit to conserve water resources in dry years. Check out a recent article about Understanding How Drought Impacts Plants in our most recent issue of Maine Home Garden News. The article outlines several examples of how plants are impacted by drought and strategies on how to minimize water stress in the future.
As a side note, many of your green fruits will eventually ripen off the vine. Don’t send them to the compost pile just yet!

Q: How do I get rid of the tomato horn caterpillar?

Tobacco and Tomato HornwormsA: Most home gardeners encounter the tobacco hornworm caterpillar in Maine gardens, but the control measures outlined in this Tomato Hornworm (PDF) factsheet from Cornell University will work on both. The difference between the 4 inch long worms is that the Tobacco Hornworm has seven diagonal strips on each side and the Tomato Hornworm has eight v-shaped marks on each side. Our UMaine Extension Home and Garden IPM factsheet shows the difference between these two insects. The easiest control is a pair of scissors to snip the large caterpillars, but for larger infestations refer to the Cornell factsheet.

Q: We have planted some butternut squash in an area that is relatively new. The plants look good at first and will generate fruit but the fruit will not ripen because the plant dies before its maturity. Therefore the fruit has not gone to full term. We are guessing there is a virus in the soil that is doing this. Can you provide an answer? What would be recommended to fix this problem? My squash plants are dead now.

A: Sorry to hear you are having trouble with your butternut squash. Without seeing a picture of the plant before it was completely dead it is hard to tell what happened. It could be a virus, fungus, bacteria, insect infestation, drought stress, or nutrient imbalance. Some things to do to reduce the chance of this happening again would be to take a soil sample (Testing Your Soil) to be sure the nutrients are balanced, plant a green manure crop in the area now to provide organic matter to next year’s crop, use varieties that are resistant to disease and are certified free of disease. Next year at the first observation of unhealthy plants/leaves take a picture and send it to us or send a leaf sample to us to identify what is happening. How to submit plant disease or insect samples: Insect and Plant Disease Diagnostic Lab. You may want to sign up for our monthly Central Maine Gardening Newsletter.

Q: I have a lakefront cottage in Maine. I want to add native plants to the spaces between the neighboring cottages to decrease noise and visibility. The soil is thin with lots of rocks and the space has lots of shade due to the height of the existing conifer trees. There is significant moss on the rocks. Can you suggest native shrubs, flowers, and trees?

A: Cedar (Thuja occidentalis), Eastern hemlock (Tsuga canadensis) and hobblebush (Viburnum lantanoides) are a couple of examples of native woody species that can survive in relatively low light and rocky/thin soils. If your screening needs are primarily in the mid to late summer months, then some tall ferns may be able to do the trick. We have an excellent list of native plants in our bulletin #2500 Gardening to Conserve Maine’s Native Landscape and have detailed bulletins in our online Master Gardener Manual on a number of native species.

Please keep in mind that it’s going to be a challenge to get anything to establish as a thick screen if the site has less than 4 hours of light a day. Your best bet is to install a variety of shade-tolerant plants, watch what does well in the conditions you have to offer and plant more of what works when you see what thrives. Starting with smaller plants will increase the likelihood of them getting well established in rocky soils. Keep in mind that wildlife can also be a factor when choosing new plants for the landscape (deer love cedar).

septic leach fieldQ: I‘m trying to find out how far away from our leach field should our vegetable garden be? I’ve found information about not growing on top or directly next to it, but want to know what a safe distance to start planting would be?

A: While UMaine Extension has a publication Vegetable Gardens and Septic Fields Don’t Mix, your question about the specific location where it is safe to plant a garden requires further information. I asked Dave Rocque, State Soil Scientist with the Maine Department of Agriculture, Conservation and Forestry to comment.

“As is so often the case, site specifics make a difference in the answer. For instance, if the garden is upslope of the leach field, you can have less of a setback than if it is downslope. Also important is the soil type. Sandy loam soils with a shallow hardpan are the most problematic and sandy soils with a deep water table the less problematic.

If you want, you can have the gardener contact me at 207.287.2666 or . I can either provide an answer by phone or do a site visit when I am in the area.”

plumsQ: We bought our first home and I was pleasantly surprised by the bountiful amount of berry and fruit trees we have. I would love to find someone to come to our home and teach me as well as prep the trees and bushes for the fall. Do you happen to have any recommendations for a knowledgeable person for this?

A: We have a great website for home gardening information that includes links to upcoming classes, factsheets, newsletter, and videos. During the growing season, many of our gardening classes are held at either the Rogers Farm Demonstration Garden in Old Town or the UMaine Gardens at Tidewater Farm in Falmouth. The Rogers Farm Demonstration Garden is having a Field Day September 10th! This would be a great time to come and learn from the experts.

tomatoes on the vine growing in a container on a porchQ: I have several tomato plants in buckets that have just flowered. Is it too late in the season to expect those plants to produce tomatoes? Should I leave them outside or take them inside?

A: Your harvest will depend on the type of tomatoes you’re growing. Smaller fruited varieties (cherry and grape types) will likely yield some tomatoes within the season we have ahead of us, but it’s tough to tell what you’ll get for tomatoes from larger fruited varieties if they’re only just starting to flower now. Either way, don’t give up on them and keep them in as much sunlight as possible. Watch for low evening temperatures. Cover with a light sheet or move to a protected area if frost is expected. Be sure to uncover during the day. Depending on the weather, this strategy can help extend the growing season for a few weeks. More season extension strategies can be found here.
When it’s time to call it quits, but your plants have green tomatoes on them, be sure to harvest and store them at room temperature to ripen. It may take a while, but if they’re somewhat developed, green tomatoes should ripen indoors just fine. Place them in a bag with another ripe fruit to quicken the process.

backyardQ: We are thinking about putting in a vegetable garden in our backyard. Should we test the soil first to see if it is viable to grow vegetables? I also want to grow blueberries and fruit trees in the center area of our yard where it is already cleared. Attaching a photo of the area we are planning to clear and the center of our yard where we want to put blueberries and fruit trees.

A: This is the perfect time of year to start your new garden. When clearing the trees, be sure to clear a large enough area so that your garden area will get at least 6 hours of sun a day. Once the trees are removed you will need to have the stumps removed and the ground leveled. After the groundwork is done you can take a soil sample. Here is our fact sheet on Testing Your Soil. Since you have plans for different types of plants you can list two crop codes and get soil amendment recommendations for both your vegetables and blueberries since they have different nutrient needs. Before winter you can amend the soil so you will be ready to plant in the spring.

For ideas on what varieties to plant check out these factsheets.

Q: When I first moved here four years ago I could find foraged ground cherries only randomly at a roadside stand or store. But for two years now, one of the farmers I buy from regularly has been selling them in much larger quantities. Is it a sustainable thing to do to try and domesticate these natively wild species? Is there a downside to cultivating wild things for culinary pleasure? Can we change them for the worse by pulling them in under the tent when they’ve been perfectly happy out in the woods?

A: Like most plants that we eat, ground cherries or husk cherries (Physalis pruinosa) have wild relatives as well as cultivated versions. You can purchase seeds for ground cherries and plant them yourself. Or, like our native wild blueberry, forage to find your own. This is a lesser-known fruit to many people now, but it has been grown in gardens and foraged where it is native for hundreds of years. Every fruit or vegetable has a wild relative, some of which look very similar but perhaps have been selected for flavor, and others that look extremely different (like the banana) and/or wouldn’t be edible otherwise. The merits of selecting plants for human consumption is beyond this scope of this forum, but without agriculture, where would we be? I encourage you to research artificial selection or plant breeding.

asparagusQ: I am looking to plant asparagus crowns this fall in Bridgton. We had poor success (8 out of 30 survived) with what we planted this spring and am looking to catch up by purchasing 2-year-old plants to shorten the time before harvest. I suspect we had poor success with the spring planting as they were not planted until early June (spent 6 weeks in the refrigerator as they were shipped much earlier than I had expected). We did water as much as possible and composted well before planting. Am I wasting my money to try to plant them in the fall or should I just try again in the spring?

A: We generally recommend sticking to one-year-old dormant crowns as older ones tend to carry more disease. It is also best to plant in the spring so your plants have enough time to develop a strong root system heading into winter. Check out Bulletin #2071, Growing Asparagus in Maine for all of the details on how to give your new planting the best chance at a long, healthy and productive life.

SwallowwortQ: We have a plant growing in our daylilies, and I’m trying to figure out what it is. It has lovely flowers, about 1 centimeter across, and it’s trying so hard to be a nice plant and not take over. Wondering if we can transplant it to my wildflower bed, or if it’s horribly toxic?

A: Unfortunately, this is not such a nice plant. This is Black Swallowwort and should be removed from your garden ASAP. In addition to our fact sheet, there is an article in the Portland Press Herald from three years ago detailing the struggle to manage this invasive plant in southern Maine. Hopefully, you’ve caught your infestation early!

Raised beds by Dennis ConnellyQ: What should be added to my raised beds (besides compost) this fall to make my garden better next year? This year’s garden grew above-ground crops, lettuce, Swiss chard, etc. wonderfully. But the beets, carrots, and radishes did not grow well. The soil test showed that we had above optimum amounts of organic material, phosphorus, potassium, calcium, and magnesium.

A: Unless you need to modify your pH, you likely don’t need to add anything. You might plant a cover crop as soon as you finish up harvest.

Q: How do I know when it’s time to pick my buttercup squash and my delicata squash?

winter squashA: To determine if the fruit is ripe, look for tough, dull, dry skin that cannot be punctured with a thumbnail. Unripe fruit will not store as well. Care should be taken to avoid bruising or cutting the fruit during harvest and fruit should not be stacked too deep (two to three layers deep at most). Stems should be cut as short as possible.

Most winter squash should be cured in a warm, slightly dry location with plenty of airflow (80-85F and 75-80% relative humidity). If the weather is favorable, this can be done in the field, but care should be taken to avoid sunscald and chilling injury during nights below 50F. Curing typically takes about 10 days. Not all winter squash types benefit from the curing process. For example, the quality of acorn varieties declines with curing. Therefore, acorn types should simply be gradually cooled and put into storage.

Winter squash store best in well-ventilated, cool, dry areas (55-60F and 50-70% relative humidity). Lower humidity will cause the fruit to dry out and higher humidity can provide favorable conditions for potential decay organisms.

Taking the time to properly harvest, cure, and store your produce will allow you to enjoy savory meals during the chilly winter months to come. Here’s a recipe to whet your appetite: Stuffed Squash.

Q: We have a garden every year and every year some of the leaves of our vegetable plants get brown and die: tomatoes, potatoes, squash, cukes. We also have carrots, beets, and onions that aren’t affected at all. What is it and what can we do? This year we used only manure in the garden to see if that would help. Any help you can give us will be appreciated

black plastic mulch and cucumber plantsA: There are very few diseases that would impact plants in two different families, so I hesitate to say that there is just one cause here. It does sound as though it is soil-borne since happens every year. Have you tried mulching your plants with straw or plastic mulch to prevent soil from splashing onto the foliage? Photographs of each plant type could help me make a determination. Or, you could submit plant samples to your local UMaine Extension county office. You might consider rotating into a new area of your yard to give that garden space a rest and avoid those pathogens next season.

Q: I have 6 rows of potatoes in my garden, and the tops are turning brown and shriveled. My husband just cut off all the foliage in case it’s some kind of blight. My root cellar is about 68 degrees. Would it be better to leave the potatoes in the ground until mid-October when it’s a bit cooler, or should I dig them now and put them in the root cellar now, even though it’s relatively warm in there?

new potatoes; photo by Edwin Remsberg, USDAA: It’s hard to say what might have caused your potato plants to shrivel. Were you keeping them watered? Do you have a history of any soil-borne diseases in your garden? You should dig a few tubers to see how they look. If they appear to be fine, keep them in the ground until September or so and make sure they are nice and dry before putting them in storage. For some best practices, check out Bulletin #2077, Growing Potatoes in the Home Garden.

Q: I have wood chips between my raised beds to keep weeds down/out. When we first put the beds in 6-8 years ago, I put cardboard and damp newspaper down as a layer between the grass/lawn and the wood chips. I am late getting wood chips down this year and the weeds are prolific and poking through all over. Should I put another layer of cardboard or newspaper down to suffocate the existing weeds, on top of the wood chips and mulch from previous years? Would that help or cause problems?

raised bed vegetable gardenA: It couldn’t hurt to do exactly what you suggest. Depending on how high the layer is now (or would be), you could choose to move it all into your compost pile and start over. If you don’t think it will be too high, go ahead and put down a nice layer of cardboard and/or newspaper, wet it down so it doesn’t blow away, and mulch with wood chips soon after. Six to eight years of weed suppression is a fantastic result, which you will hopefully achieve again!

Q: Why are the leaves of my corn growing in containers turning brown?

A: There are many reasons corn leaves turn brown: drought, N-deficiency, N-burn, rust fungus, insect injury…. It’s difficult to say what might be going on without more information.

Q: I have some very large white grubs in my garden. Curled up, they are at least an inch across. There are hundreds of them. I bought the soil from a landscape company, which told me it was organic. I’m guessing it was from compost that wasn’t cooked enough. I’m not sure what to do about it or if they are harmful. I’ve looked at lots of different photos of grubs. They look similar to most white grubs, except they are very big.

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.A: It can be very difficult to ID white grubs without magnification. They all look very similar at that stage. I recommend submitting a sample to our pest management office. Management strategies will depend on which species you are dealing with.

Q: I want to grow white grapes on my patio. Is it possible to keep grapes in large pots on an arbor as it would be impossible to move? Which white grape for making wine would you recommend?

Edelweiss grapes on the vine
Photo by David Handley.

A: I found one reference to growing grapes in containers, which recommended at least 15 gallons of soil per plant. I do not think your plants would be happy enough to produce grapes for wine production. I recommend spending some time with Small Fruit Specialist David Handley’s Growing Grapes in Maine for all of the details of recommended production practices. It couldn’t hurt to try one plant in a (very large) container, but I wouldn’t invest a lot of time or money in that system.

Q: Our mature (but not ancient) peach trees have flowered and produced fruit in the past. They didn’t flower last year or this year. Our mature apple trees (also relatively young, but full size) have also produced well in the past but gave only a minimal crop last year and no flowers this year. Our trees have been carefully pruned and look healthy. Should we fertilize them? We didn’t apply fertilizer last year and haven’t yet this year. We live in Cornish, Maine at 750 feet elevation.

ripe peaches on treeA: A soil test is never a bad idea, though I suspect you may have experienced a killing freeze following some unseasonable warmth that did in any of the fruit buds initiated last fall. Do you know if there were flower/fruit buds heading into winter? Are they hardy varieties for Maine? You did not mention a pest management plan. Have you sprayed your trees to prevent disease and insect infestations? Bulletin #2411, Planting and Early Care of Fruit Trees and Growing Fruit Trees in Maine might give you some more information about general care for your peaches and apples.

Q: What is the difference between blackberries and black raspberries, and which would grow better in Washington County. I do not have full sun all day. Also, should I wait until spring or could I plant now if I could find some?

blackberryA: Check out Bulletin #2066, Growing Raspberries and Blackberries for everything you need to know about establishing brambles on your property. They do best in full sun, but if you’ve got at least six hours in a well-drained area they will likely be okay. It is too late this year to plant, but there is still much you can do now to prepare for planting next spring. Blackberries and black raspberries are two different species. The plants grow differently and the fruit of blackberries is generally firmer, larger, a bit more tart, and is not hollow like a raspberry (of any color) is when harvested.

Q: What is a resource for sterile/organic composted manure in the Orono-Old Town-Bangor area?

A: We cannot recommend specific vendors, but you could contact your local Extension office in Bangor for some ideas.

Q: Our location is in Zone 4. We’re hoping to build the health of our fields by planting a cover crop this fall. We have a large amount of clay in the fields. Please advise us on a cover crop choice. We plan to grow crops in the fields again next spring.

A: Cover crops are used for a wide variety of purposes. Without knowing your goals, it’s difficult to make specific recommendations. Check out Cover Crops for Home Gardeners for some quick suggestions and refer to the list of references included at the end for more details.

young broccoli and cauliflower plants in raised bedQ: I transplanted six broccoli and six cauliflower plants into a raised bed the week prior to Memorial Day. None of them have sprouted a head yet (see photo). Should I consider them done? Or is there still hope for heads to form?

A: They look perfectly healthy. Give it some more time.

Q: Our garden is really struggling this summer. The peas are dying from the bottom up. All of our broccoli, kale, and kohlrabi has scarring on the stem, and the leaves are shriveling up and dying. Also, the basil is browning/blacking from the tips of leaves. Thanks for your help!

A: Many gardens are struggling this year due to the lack of rain and fluctuation in temperatures. Are you watering your garden regularly? Aside from maintaining soil moisture for plants to use, you want to be sure nutrients are mobile. Some of what you’re seeing could be due to hail damage — I know my plants are still recovering from a hail storm a few weeks ago, as well as chilling injury from the cool weather. Your basil may have a disease like downy mildew. You should remove any leaves that are turning black or any plants that show these symptoms all over to prevent the spread. Overall, maintaining consistent watering and protecting your plants from cool temperatures and wind with row covers should help.

Q: I moved into my home in Waterford in September of 2014. Most of the 1-acre lot is wooded; the area around the house had not been well maintained. The soil is sandy, rocky, and I think rather acidic due to numerous evergreens around the property (see photos). My funds are limited and there is much to do, but in order to obtain successful results (a nice, thick lawn) I need to know the order in which to treat the soil and to begin planting. Most of the backyard is in deep shade for at least part of the day in summer. Additionally, at the back of the house is a steep hillside and the dirt is eroding. So first, how do I stop the erosion; next, how do I treat the soil so as to encourage grass growth? What border plants would work best both inside or outside the fence, and as foundation plantings?

A: Your first step should be a soil test to determine the current pH and nutrient levels of the soil where you wish to establish grass. Bulletin #2367, Establishing a Home Lawn in Maine will take you through the decision-making process and help you choose the products and processes that will work best for you. To manage erosion on the hill, you should establish plants that will fill in quickly and hold the soil in place with their root systems. You might decide to plant grass here as well, or you could use other, lower-maintenance plants. To help you choose plants for each purpose in your new yard, I recommend Bulletin #2500, Gardening to Conserve Maine’s Native Landscape: Plants to Use and Plants to Avoid, which includes a chart to help you choose the best species for each purpose.

Q: I have a small amount of gypsum wallboard (sheetrock) left over from a remodeling project. If I remove the paper sheathing and crush the chalky material inside, can I use it as a soil amendment? Can I work it into my compost pile?

A: If this is new, unused drywall that has no paint or other materials on it, you could do this. Gypsum will increase the calcium content of your soil. There is no benefit to your compost pile, but it probably would not be a problem either. Be sure to wear eye protection and a mask when crushing it as it will become very dusty.

North Star cherry tree with brown rotQ: My North Star cherry tree looks like it has brown rot. Can you confirm (see photo)? The tree also has some clear hardened sap-like substance (it looks like epoxy) on the branches. It looked good this spring, produced lots of flowers, and then when we got back from vacation the flowers were brown and it seemed like there was less green foliage, too. This is the only year we’ve had trouble with the tree (planted in 2009). It’s always produced a lot of fruit, but there are very few berries this season.

A: This does appear to be brown rot, which you can read more about in Pest Management Fact Sheet #5090: Brown Rot of Stone Fruits. An excerpt from this publication recommends these control measures:


Fruit infections arise from spores that are produced on recently blighted blossoms and cankers. It is important, therefore, to control the blossom blight phase of the disease.

  1. Remove all fruit from the tree and from the ground and prune out infected twigs after harvest. Burn, bury, or otherwise remove these infections from the orchard. This practice will reduce the number of spores present the following season.
  2. Destroy wild Prunus spp. in the vicinity of the orchard because they may harbor the fungus.
  3. Prune the trees to maintain good air circulation which will promote rapid drying.
  4. Sprays to control the blossom blight phase are the most important. Fruit should also be protected during the three-week period before harvest. The following table lists labeled fungicides. See labels for specific timings of sprays.

cucumber seedling with damaged leavesQ: We planted these pickling cukes 2 weeks ago and 3 out of the 6 plants have at least one leaf that looks like this (see photo). The white is dead and crunchy. What is wrong?

A: It looks like it could be a chilling injury. Cucumbers can become chilled at temperatures below 50 degrees, which we have experienced overnight recently. If your plants all have healthy looking foliage as well, they should grow out of it.

Q: Should I trim the bottom leaves of my tomato plants that are touching the soil? The plants are about a foot tall.

A: If you have a history of soil-borne foliar diseases (like early blight) and no mulch, it may reduce or delay infection to prune off the branches close to the soil. For more on staking and pruning of tomatoes, check out the video How to Grow Tomatoes: Staking.

Q: I have a volunteer flowering plant that I’d like help identifying; my local nursery has no idea what it is, but I saw it planted as an ornamental in a city park this past weekend. I’d like to know how to care for it, as it currently opens its flowers for only about an hour a day, so I’m wondering if it would prefer shade instead of the complete sun it gets in its volunteer location. The plant grows to about 3 feet tall and has yellow flowers with red streaks. When it goes to seed, it looks like a dandelion. See my two pictures.

A: This appears to be yellow hawkweed, which is considered a noxious weed. It is very adaptable and can establish itself in most soil conditions. The flowers tend to close each evening, regardless of location.

invasive weed

Q: I have two questions regarding problems caused by very bad feed hay I bought for mulching my vegetable garden. One was a serious health effect from mold and the other an awful invasive weed problem. Question 1: Are there any regulations regarding the sale of bad hay? Question 2: Can you ID the weed that’s taken over my garden (see photo) and recommend the best way(s) to get rid of it? Will I have to give up my garden space this summer to do something like the “solarization” process you recommend for weeds in your 2015 vegetable and fruit Q&A webpage (very helpful info for many topics)?

A: I am sorry you had a bad experience using hay as mulch in your vegetable garden. You have outlined all of the reasons I never recommend using hay for this purpose. To my knowledge, there are no regulations regarding the quality of hay for sale in Maine. It is a buyer-beware situation and forage testing should be done before purchasing any forage for feed. Mulch hay is usually not high enough quality to feed livestock and is better used for lawn establishment, erosion control, and other purposes. Hay always has weeds in it. Hay is never weed-free. This is the most common way weeds are introduced to new areas. The weed you have acquired appears to be one of the mustards. Preventing plants from going to seed is a priority, and yes, solarization may be an effective strategy for you. If you put the plastic down now, you may still have time to put in some fall crops later in the season.

red lupineQ: I purchased a red lupine, which grew successfully for two years. Absolutely beautiful. This year, it is purple. Curious to hear your thoughts.

A: The flower color of an individual lupine plant does not change from year to year. It is possible you are seeing the results of a cross-pollinated seed that fell from your original plant.

Q: I have planted cucumbers in hills in a fenced, raised bed. Once they germinated and had two leaves each and were about a half-inch high they simply disappeared as if something had eaten them. I checked the fencing and am sure nothing got in through it and there were no footprints. In another bed, about a half row of newly sprouted peas disappeared and there were very slight indentations in the ground where the plant was. There are no visible holes in the ground. I am thinking it might be slugs.

Slug. Photo by Griffin Dill.

A: It could be slugs, particularly if your garden is in a shady location and is naturally damp or over-watered. There are lots of small critters that would like to snack on a tender seedling, so it’s hard to say for sure. Is your fence tight enough that rodents cannot get through? They are another possibility. If you still suspect slugs, you can try trapping them by laying out flat boards or damp newspapers in your aisles. Check underneath them first thing in the morning to see if they are hiding there.

Pest damage on vegetable seedling.

Q: There is something in our garden eating our plants (see picture). I was wondering if you could help identify it might be and what we can do to stop it. I’ve been spraying a garlic, soap, and cayenne mixture, but this doesn’t seem to be helping.

A: This looks like a cutworm injury to me. Here is an article from the Maine Home Garden News that includes tips on managing this early season pest.

Q: Can you eat vegetables from soil where a car was parked for 20 years? The car fluids were drained a long time ago and there is apparent rust on the ground.

A: I recommend at least getting a soil test, which includes a lead scan. Other heavy metals are not part of a standard soil test, but could potentially be present. If you think there is any chance there is something in the soil that you would not want to eat and this is the only place you have for a vegetable garden, I recommend raised beds.

Q: We recently planted some vegetables in a raised bed and something is digging holes in it. It does not dig the plants but is digging in the soil at the edges of the bed. What can this be and how shall we prevent this? There is no evidence that cats are doing this digging.

mini-hoophouse with plastic cover pulled back for ventillation
Photo by Caragh Fitzgerald.

A: I cannot say for sure what may be digging in your raised bed. You might consider a barrier of chicken wire or hardware cloth along the edges and (potentially) over your raised beds to prevent your vegetables from becoming someone else’s dinner. Creating a hoop structure over your beds allows you to change out the cover for various purposes — clear plastic to conserve heat early and late in the season; remay to keep in heat and rain and exclude insects; or chicken wire to exclude animals.

Q: This is not about growing vegetables, but maybe you can steer me in the right direction. Over the winter, deer have nearly decimated 3 lovely rhododendrons in my yard. They are now in bloom, miraculously, but I am wondering how I can help them survive the future. Should I fertilize them once they have finished blooming? And what fertilizer should I use in the case of such severely denuded shrubs?

Rhododendrons in bloomA: Before applying any fertilizer, do a soil test. You can pick up a free kit, including instructions, submission form, and a box at your local Extension office. Fertilizers should only be applied to perennial landscape plants when the pH is not appropriate or if there is a clear nutrient deficiency. If your rhododendrons are otherwise okay, your focus should shift to protection from deer damage or replacing them with species deer do not like to eat.

Q: We have a small greenhouse that we don’t heat. We started our seedlings and got a good crop of early lettuce and radishes. We have put in tomato and pepper plants hoping to get earlier produce. What can I plant now to take advantage of the greenhouse and extend my harvest?

High tunnel with sides rolled up
High tunnel with raised beds. Note roll-up sides. Photo by Caragh Fitzgerald.

A: We are getting into the time of year when we will need to worry more about excessive heat in a greenhouse or hoop house than capturing it to push early plant development. That said, there are warm-season crops that will do very well in a house over the summer, provided you can supply the proper ventilation and irrigation. Many commercial producers use their houses to grow tomatoes, peppers, and cucumbers through the summer. These plants can take advantage of the extra heat and enjoy vastly reduced leaf wetness from rain (by using drip irrigation) which makes disease management much easier. If your structure can support trellising plants on strings up to the trusses or ridgeline, you can get quite a few plants in there and it becomes easier to prune and maintain airflow. You can also continue to start seedlings for succession plantings of short-seasoned vegetables in your garden. In August, I recommend starting greens for over-wintering inside and cole crops like broccoli, cabbage, and Brussels sprouts for late-season production in the garden. You will find more information in Bulletin #1022, Maine Season Extension Options: Making the Right Choice for Your Farm and Bulletin #2752, Extending the Gardening Season.

young apple tree with pest damage

Q: We planted several fruit trees this spring and something is eating the leaves of two of our apple trees. Do you have any ideas what it might be (see picture), and what we should do about it?

A: Judging by the feeding injury and the frass (waste) on the leaves, I believe you have some kind of caterpillars feeding on your apple trees. Eastern Tent Caterpillar is very active right now, but there are others you may be seeing as well. You should physically remove any nests or insects you can find and you may also choose to spray B.t. (Bacillus thuringiensis), spinosad, or insecticidal soap. Be sure to follow the instructions on the label precisely. (Take extra precautions if you think you have browntail moth to prevent any of the hairs from touching your skin.) Apples have many pests, so you should monitor them each day and have a plan in place to prevent insects and diseases from damaging your trees. Growing Fruit Trees in Maine can help you get started.

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: We live in the greater Bangor area and have a significant grub problem. Can we treat the lawn pre-emergently in June for grubs and reseed with new topsoil at the same time? We would then treat for mature grubs in the fall.

A: That should be an effective strategy for you. Treatment of white grubs is dependent on the life cycle of the species you have. A multi-pronged approach should help you get them under control.

Q: What do I do to lower the pH in my soil?

A: For long-term reduction in pH, incorporate elemental sulfur to a depth of at least six inches.

Q: I am planning a 12′ x 8′ vegetable garden, with the usual veggies, tomato, lettuce, etc. What is a good watering schedule? I will be watering via hose this first year.

Two women plant seeds in vegetable gardenA: Your garden will need the equivalent of 1-2″ of water per week during the growing season. Since we’re already very dry for this time of year, be sure to water your transplants in very well and monitor the garden soil each morning and evening. If your plants start to look a bit wilted, they need water immediately. Using your garden hose is fine, but you may consider a length of soaker hose so that you can prevent the leaves of your plants from getting wet unnecessarily (preventing disease) and conserve more water. Once you have a season under your belt, you might consider drip or trickle irrigation which you may read more about it in Bulletin #2160, Trickle Irrigation: Using and Conserving Water in the Home Garden.

Q: I would like to plant marjoram, lovage, and lemon verbena in my garden in York, Maine. Do you know the best dates to plant these herbs?

A: You may plant these herbs once the danger of frost has passed. Memorial Day weekend is a very common time for frost tender plants to be planted in the garden, so any time now is fine. If you are putting in transplants (instead of seed), be sure to water them in well and avoid planting in the heat of the day.

Q: I have 5 raised beds: 4x8x2, 4x4x2 (one of these is asparagus that didn’t come up this year after 3 years), and 2x4x1. The seeds I planted in the 4×8 beds are all growing better than those in the smaller beds. All the beds are on the south side of the house and receive comparable (not identical) sunlight and the soil analysis is similar. The boxes are filled with purchased compost, my own compost, purchased supersoil, and local soil. I applied blood meal as recommended and some BT this season. Any idea why my plants aren’t growing better?

raised bed garden

A: It appears that you are suffering from too much of many good things. Based on your soil test results, most of your nutrient levels are much higher than is optimum for vegetable growth. It may be counter-intuitive to think more nutrients are a bad thing, but they can cause problems, which I suspect is what is happening here. In addition, your pH is on the high side of ideal, making all of these abundant nutrients even more available than they would be if you had a lower pH. We often see this in high tunnels where there is no rain to wash through the soil and over-application of compost is fairly common.

You can see a handy chart and read more about this phenomenon at the University of Missouri’s website.

Since we are in the planting season, I recommend applying lots of water and some sulfur to lower your pH and try to leach out some of the nutrients in your soil.

Q: We want to replace our lawn with low-maintenance, sustainable alternatives that grow in Maine. We’ve been reading about edible lawns, but most are in California. Ideas?

butterfly landing on purple flower
Photo by Desiree Butterfield-Nagy.

A: While a low maintenance landscape and an edible lawn are both great goals, they may be mutually exclusive. There are many ways to make your home landscape lower-maintenance, from using slow-growing grass species, nixing herbicides, fertilizers, and regular pruning in favor of a more natural look, and reducing the grass by putting in more perennials and trees that don’t need weekly attention. An edible lawn (or garden) on the other hand, has a lot of benefits, but would not be considered “low maintenance,” particularly in Maine’s short growing season. University of Florida Extension’s Landscape Design with Edibles will give you a great start on how to approach your design. Of course, if you stick with perennial shrubs and trees, there will be less maintenance than if you want to incorporate vegetables.

Q: I want to apply manure to an open area, incorporate into the soil with a rototiller, and plant rye as a cover crop. I am not looking to harvest anything edible from this land this year. How close to my well can this strategy be used? I have read from different sources that 100 feet is acceptable — but I am wondering if UMaine Extension has a rule that you go by?

Farmer on tractor tills a new fieldA: If the ground were frozen or you were planning to stack (or store) manure from livestock, there would be other considerations, but since you are planning to immediately incorporate the manure you apply, there is a low risk of run-off; 100 feet should be an adequate distance to maintain from your wellhead.

Fresh manure is often a source of weed seeds (composted manure has significantly less weed seed). You will want a cover crop aggressive enough to out-compete any unwanted seedlings. Rye is an excellent choice for a fall-planted cover crop because it dies over the winter before it goes to seed and protects your soil from erosion. Spring and summer planted cover crops are usually succession plantings of buckwheat and clover, which will suppress weeds and add fertility to your soil at the same time. You need to be careful with whatever species you choose and not allow anything to flower and go to seed; it will become a weed problem for years to come, otherwise.

If you are planning to apply the manure and till it in, I would till again 3 days later and seed that afternoon. Allowing the manure a little time to decompose will help to ensure the high N levels do not burn your cover crop seed.

Q: I recently planted some carrots, and noticed that there were a boat-load of small brownish ants in the garden. Will they take my seeds? Are they harmful?

ant on flower
Pavement ant (Tetramorium caespitum). Photo by Joseph Berger,

A: With thousands of ant species in the world, and more than a few here in Maine, it is not possible to make a blanket statement about whether ants are harmful. Many ant species are very beneficial, helping to aerate garden soil and cycle nutrients. Many species will also eat known garden pests. While some ants will take seeds back to their nests, I doubt they are particularly interested in your carrot seed. Keep an eye on your planting and watch for a disturbance. If you want to know exactly what these particular ants are looking for, you should send a sample in for identification.

Q: I’ve had a vine-weed growing in my yard for 2 years: small, dark green, roundish leaves with hair-like prickles, and tiny blue flowers at this time of year. The vine goes under the soil and spreads all over — when I pull one, several across the yard are connected, leaving babies to reproduce, unfortunately. It causes my dog’s feet to itch, and I won’t go barefoot on it. So far it’s taken over a 20′ x 40′ plot and is spreading! Do you know what this is and how I can get rid of it?

A: It’s hard to identify your invasive weed without a sample or photos. I recommend bringing a sample of this plant, including flowers, to your local extension office for identification, or take some high quality, digital photos and email them. Once we know what your plant is, we can suggest options for managing it.

newly planted fruit tree whipQ: I’m planting apple whips. Do they prefer fungal soils or bacterial soils?

A: Apple trees can tolerate a range of soil conditions, but pH and drainage are the two biggest concerns. Growing Fruit Trees in Maine — Planting and Early Care provides a good summary of the conditions your young trees will thrive in.

Q: I have a blueberry plant that is a single cane. Is there anything I can do to promote more canes?

A: If your plant is leafing out and you are you sure it made it through the winter, check out the fertilizer section of Bulletin #2253, Growing Highbush Blueberries. Blueberries, unlike most garden crops, require an acidic soil. You may be able to encourage more cane development by adding ammonium sulfate, making sure there is no weed competition and supplying adequate water.

late blight on tomatoes
Tomato plants infected with late blight.

Q: At the end of last summer, my tomato plants got late blight. I got rid of the plants. They started well and I was able to harvest some tomatoes. What do I need to do this year so that my tomato plants will not get this again? Is there any way to prevent late blight? I’m worried that it might be in my soil now. I live in Presque Isle and I grow my tomatoes in a raised bed.

A: Late in the season when the weather is warm and humid and late blight spores are around, it can be very difficult to prevent your tomatoes from getting this disease. Luckily, the fungus cannot overwinter in the soil or on tools or pots, so we always start the season with a clean slate. Check out Bulletin #2427, Tomato and Potato Late Blight Information for the Upcoming Growing Season for more information on late blight and how to give your tomatoes (and potatoes) the best chance at success this year.

Q: If potatoes have sprouted and the sprouts break off, will they regrow?

A: Sprouted table potatoes are not designed to be used for seed. If you are planning to plant potatoes in your home garden this year, check out Bulletin #2077, Growing Potatoes in the Home Garden, which includes information on seed potatoes. Bulletin #2412, Selecting, Cutting and Handling Potato Seed goes into more detail about the seed itself.

Weeping Willow (Salix species)
Weeping Willow (Salix species). Photo courtesy of Dow Gardens , Dow Gardens,

Q: I live in Hancock and was wondering if weeping willow trees can grow here.

A: Weeping Willow (Salix species) is a very interesting, though somewhat high-maintenance, tree in the home landscape. There are some varieties that could survive in Zones 5a and 5b. I recommend going to a locally-owned garden center and selecting a variety that they carry.

Q: I have a few arctic fire dogwoods. The branches were a dull orange all winter, and now they are turning black on the tips. Are the plants sick? Not getting enough sun? Getting too wet?

dogwood stem
Redosier dogwood (Cornus sericea). Photo courtesy Paul Wray, Iowa State University,

A: It’s hard to say what is going on with your dogwoods without a sample or photos. Have you been pruning your shrubs each spring after they flower? If they get too dense, they are more likely to get diseases. Also, older canes will lose their nice, red color. Winter injury is possible, though not as likely since they are a hardy plant to Zone 2. If they are in full shade or a damp area, these could also cause problems. If you can, take some high quality, digital photos and email them to your local extension office for diagnosis.

Q: Live in Waldoboro and ants have taken over the lawn. Just piles of anthills. How can I reclaim my lawn without poison?

A: Ants are generally a very brief nuisance in our home landscapes. The first step is to identify the species you are seeing to be sure they are not invasive European Fire Ants. If you are reasonably certain they are one of the more common varieties, this article from Iowa State, called Ants in the Lawn, may be of assistance.

milkweed seedsQ: At my previous home I had a lot of milkweed, which attracted butterflies, including monarchs. At my new home, there is no milkweed. Where can I find seeds or plants?

A: The Xerces Society for Invertebrate Conservation has a Milkweed Seed Finder on their website. There are several results for Maine vendors, including Native Haunts in Alfred and Wild Seed Project in Blue Hill. You can also plan to save seeds later this season from wild milkweed in your area.

Q: We just bought home with 1/3 acre in Bangor. I would like to grow vegetables and herbs in part of the yard and maybe have a greenhouse. What’s the best way to convert the grass to garden?

Solarizing a garden plot with clear plastic mulch
Solarizing an area with clear plastic mulch. Photo by Marjorie Peronto.

A: I do not recommend trying to plant into sod this year. In the areas you would like to convert to garden spaces, I recommend a soil test first to be sure there is no lead that would make food crops unsafe. If the lead levels are not a problem, you first need to remove the sod or otherwise kill the grass, which will become a major weed problem if you try to simply rototill and plant this year. Solarization, described in more detail in Bulletin #2752, Extending the Gardening Season, is a good way of doing this without the use if herbicides or several seasons of other cultural practices. If your soil does have high levels of lead, or your soil would require a lot of amendments to make it appropriate for gardening, you might consider raised beds. Bulletin #2761, Gardening in Small Spaces provides a good introduction to creating raised beds. The Home Gardening Information — Vegetables page on our site includes many useful publications, and videos on specific topics to help you further plan your new gardens.

Q: This is my second year living and gardening in Auburn, Maine. Last year we had a greenhouse built and the ground was rototilled. Do I need to rototill every year? Right now even with the greenhouse completely open, it’s mucksville in there! I have my seedlings started under grow lights in the cellar. I know I can’t plant or, if need be, rototill till the ground is much drier.

compost; photo by Edwin Remsberg, USDAA: Unless you need to incorporate amendments, cultivate for weed management, or prepare a seedbed, you may not need to rototill. Tillage is sometimes appropriate but does have downsides (particularly on wet ground) that include the destruction of soil structure, bringing weed seeds to the surface to germinate, and compaction. Soil and Plant Nutrition: A Gardener’s Perspective is a great resource to learn more about soils.

Q: We have a huge forsythia bush. Actually, I think there are 3 separate plants, each really large. They spread into each other, like a wall. It hasn’t been pruned for at least 5 -6 years. Probably more. Last year, it didn’t bloom; this year it has started to bloom on the bottom, so far. Should we prune according to your video ‘pruning forsythia’ or is there any merit or recommendation to take all of it down to about 18 inches of the trunk and start new? I heard it called ‘restorative pruning’ once, but I could be wrong about the term.

A: I recommend sticking to the concepts laid out in Bulletin #2513, Pruning Forsythias in Maine. You can plan to take out a lot of the extra branches once it has finished blooming in a few weeks, and then do more of a complete pruning next winter. This will also allow you to maintain a more natural shape than if you simply cut the entire hedge down to a uniform length.

Q: My soil is deficient in potash and nitrogen. I’ve read that black mulch depletes nitrogen in the soil. Is there a nitrogen-loving black mulch I can use?

A: Nitrogen is the one macronutrient not measured on a standard soil test because it is so ephemeral. Rain, heat, and tillage can all impact soil N on a daily basis. Soil with good organic matter content can hold on to N better, so a fall application of manure or compost is a good way to start. We generally recommend that you plan to apply all of the required N for your vegetables and fruits each season. There will be some in the soil that becomes available over time, but not enough for the high demands of summer vegetables. Mulching has other benefits, including water conservation and weed suppression, and in the spring, that extra heat does your plants a lot of good. Bark mulch or straw will not heat up in the same way that black plastic does, but may not be as practical in a vegetable garden. There are many options for increasing N fertility and fewer options for good weed control and water conservation. I would not skip the mulch simply for N conservation.

Witches' Broom (Pucciniastrum goeppertianum)
Witches’ Broom (Pucciniastrum goeppertianum). Photo by Bruce Watt.

Q: We have tried growing high bush blueberries and keep getting witches broom, which ruins the bush. Recent research revealed that proximity to fir trees could be the reason. We do have lots of fir trees with numerous witches brooms. Is there anything we can do, short of cutting all our fir trees (not an option) or using chemicals that will allow us to grow high bush blueberries?

A: You are correct that an alternate host of Witches’ Broom (Pucciniastrum goeppertianum) is balsam fir. The only management strategies are maintaining a distance of at least 1,000 feet from balsam fir trees and pruning out the infected canes of your blueberry bushes as soon as they begin to emerge. It is a systemic disease and there is no recommended pesticide to manage it. Some varieties seem more or less resistant, but there have been no conclusive studies about this issue specifically. You could try a few different varieties and see which do best in your area.

strawberry blossomsQ: When using floating row covers or row tunnels for strawberries, will I get fewer berries if my plants are covered during the time they are blossoming and bees cannot get to the blossoms? Should I uncover it at that time? I’m growing ever-bearing strawberries, seascape variety.

A: Yes, you will need to uncover the plants during the day to allow for pollination.

Q: Can I grow Baptisia in my yard near a rock ledge?

A: Most baptisias prefer and grow best in deep, rich, moist but well-drained soil. You can read more about false or wild indigo on Clemson Cooperative Extension’s website.

Q: I built a small home in Searsport on the coast. I have a septic system. I would like to plant native grasses/perennials on the drain field to prevent erosion. I know you should not plant trees or anything that has deep roots. Typically, the builder just puts in grass seed. I don’t want to have grass to mow on the drain field. In fact, I don’t want grass to mow anywhere on the acre that I own. Do you have any suggestions of what, and where I can find some native plants/perennials that would work? The drain field gets southern exposure and is about 100 yards or so from the Bay.

Viola sororia. Photo by Jennifer L. D’Appollonio.

A: Septic systems are designed with grass on the leach field because grass is a shallow-rooted plant and mowing promotes transpiration and evaporation of moisture — the goal for a leach field. Grass is considered the gold standard for this purpose. It is possible to establish other plants here (though never vegetables), but rototilling is not recommended and you should steer clear of any woody species. You could look at some perennial, native herbaceous options in Bulletin #2500, Gardening to Conserve Maine’s Native Landscape: Plants to Use and Plants to Avoid, but be very careful when selecting plants so that you do not accidentally ruin your brand new leach field.

Cornus canadensis
Bunchberry (Cornus canadensis). Photo by Dave Powell, USDA Forest Service (retired),

Q: I would like to plant a groundcover with a strong root system on a hill to stabilize the slope and prevent erosion. The hill faces east and is shaded by deciduous trees in the summer. Is there a low-growing evergreen shrub or other plant that is not invasive and may even produce berries for wintering birds? We are in Kittery Point.

A: Bulletin #2500, Gardening to Conserve Maine’s Native Landscape: Plants to Use and Plants to Avoid includes a handy table of native species by preferred habitat, including ground covers that do well in shade.

Q: Last year we started out with a bed full of strawberry plants that flowered profusely but formed no fruits. I noticed a lack of bee-type visitors to the garden throughout the summer. Could this be the problem with fruit formation and if so how do I get more pollinators to visit?

Frost injury to strawberry flowers and leaves.
Frost injury to strawberry flowers and leaves. Photo by David Handley.

A: It’s difficult to say why you had no fruit one year later, but if there was a hard frost or freeze while your strawberries were in bloom (and they were not protected by row covers and/or irrigation), that would certainly have damaged the flowers enough that no fruit would have formed. Strawberry flowers are very susceptible to cold and a frosted or frozen flower will have a tell-tale brown center instead of yellow. There are many types of insects that can pollinate strawberries, though bees are best known. I doubt that there were no available pollinators, even though bees were scarce. Bulletin #7153, Understanding Native Bees, the Great Pollinators: Enhancing Their Habitat in Maine will help you plan for a more pollinator-friendly yard using native species. Of course, I do not recommend using any insecticides in the home garden, particularly those that may impact bees. I also recommend Bulletin #2067, Growing Strawberries for more information.

Q: I live in Cumberland, and I want to apply a crabgrass preventer/fertilizer before the crabgrass comes up. This has been something of an odd winter, so it’s hard to know exactly when to apply it. I know that there is a short window between too early and too late, and I want to make sure I act within that window.

A: I do not recommend herbicides in a home landscape, and never in combination with fertilizer — especially in the spring. If you have a new or young lawn, fertilizers should only be applied in the late summer when grasses need to build their root systems ahead of the winter. With the exception of a situation where toxic plants (like poison ivy) require more than mechanical or cultural controls, application of herbicides in a home landscape is unnecessary. I recommend learning more about how to maximize the health of your lawn in Bulletin #2243, Maintaining a Home Lawn in Maine and Bulletin #2166, Steps to a Low-Input, Healthy Lawn, and for much more, see the Master Gardener Manual chapter on lawns. A soil test can tell you if your lawn is lacking any nutrition and getting one now gives you plenty of time to plan any recommended amendment applications for early September.

Q: How long is the growing season (number of days) for Solon, Maine (Zone 4b; ZIP 04979)?

Wax paper hot caps covering plants and being held down with rocks.
Wax paper hot caps covering plants and being held down with rocks. Photo by Marjorie Peronto.

A: Knowing your plant hardiness zone is useful when choosing perennial plants for your property as it is an indicator of the lowest temperatures a location is likely to experience in winter. The growing season is typically defined as the frost-free days for a given location. In central Maine, the last frost in the spring is generally in mid-May and the first each fall is generally mid-September. If we chose the midpoint for each month, that leaves about 126 frost-free days. Aside from frost, the soil temperature also plays a large role in determining when you can plant seeds and annuals. While peas will germinate in cooler soil, sweet corn will require a much warmer growing medium and therefore reduce your growing season for that crop. You should consult seed packets and catalogs to see the specific requirements for each vegetable you intend to plant. If you have plants that are particularly sensitive to frost, such as cucumbers or tomatoes, you can add protection to extend the growing season and gain a few more days on either end. Commercial producers will often invest in more significant infrastructure, such as those described in Maine Season Extension Options: Making the Right Choice for Your Farm.

Q: I am in the planning stage for a vegetable garden in Jonesport, ME. The site is open to the ocean from east to west. The area gets good sun (when it’s not foggy), but the winds are strong and there are no obstructions. The ocean does tend to moderate the temperatures. Soils will not necessarily be local. Plantings will be in raised beds. Are there any references recommended for vegetable gardening in these conditions?

plants growing in a hoop houseA: If we were talking about perennials, I think there would be some good options, but this is a very tough site for a vegetable garden. Your main problem will be wind. Many of our typical vegetable garden crops cannot tolerate high winds and fog would be problematic for disease management. If we set aside the fog issue, you could invest in windbreak plants that will make this a more hospitable site for vegetables, though that will likely take a few years to establish. Something you might consider to mitigate both issues is growing in a high tunnel. While it is geared towards farmers, Bulletin #1022, Maine Season Extension Options: Making the Right Choice for Your Farm, will give you an idea of what that might entail. If you decide to explore high tunnels further, there are myriad resources available online, including low-cost structures and YouTube videos on how to construct them.

Q: My new neighbors recently cut down an area of bamboo that grew on a banking between their house and mine. Now I have no privacy. Is there a fast-growing shrub that I could plant on my side of the property line that would block the view? Would John Clayton and Mandarin honeysuckle be good choices? I have some bamboo on my property that I want to get rid of, too. Any suggestions?

Japanese KnotweedA: I recommend Bulletin #2500, Gardening to Conserve Maine’s Native Landscape: Plants to Use and Plants to Avoid for some ideas of what to consider, and what not to consider (including any of the honeysuckles, Lonerica spp.). You will find a list of native species at the bottom that includes information about the location you are planting into and the characteristics of the plant. In your situation, you might consider one of the Amelanchier species. Removing Japanese Knotweed (bamboo) is tricky. It usually takes a significant effort and several years to eradicate it. If your new neighbor has been successful, you might ask how they did it!

Q: When is the best time to plant strawberries and corn? We use garden boxes.

strawberriesA: Bulletin #2761, Gardening in Small Spaces will give you some good tips on planting various crops in boxes or other containers. Strawberries can do well in containers, but keep in mind that they will not fruit in their first year, so you will need to get plants that are at least that age to get fruit this year. Alternatively, you could plant dormant crowns this spring and overwinter them for a crop next year, and several years after. For more information, check out Bulletin #2067, Growing Strawberries. You can plant as soon as the threat of frost has passed, usually late May or early June.

I usually do not recommend sweet corn in raised beds or boxes, simply because it takes up so much space and requires a lot of nitrogen. If you are set on it, you should read the seed packet to be sure you can produce a crop in our short growing season (no more than 80-85 days to harvest) and plant as soon as the soil temperature has reached the minimum stated, usually 65-70 degrees.

Q: I watched your video about pruning raspberries, which shows a trellis system. What is the trellis made of?

A: The video you watched, How Do I Prune Raspberries? (below), features a planting at Highmoor Farm where the trellis is built with U-Channel (highway sign) posts and pre-punched angle iron. This makes it easy to thread through the galvanized wire. You can see drawings and descriptions of several trellis systems, including the one in the video, in Bulletin #2066, Growing Raspberries and Blackberries.

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

Q: My husband purchased Permethrin SFR online to mix and spray on our clothing, but the instructions that come with the product do not list that as one of its uses. Is this a safe product to use on clothing to help prevent ticks from biting or should we look for something else? We also raise chickens that we house temporarily in one of our greenhouses. If the product is okay to use on clothing, would any residual trace left when working in the greenhouse be bad for our chickens?

A: Permethrin (36.8%) is commonly used as a tick repellent. You can purchase clothing already treated with permethrin, but you may also do it yourself. I recommend this video from the University of Rhode Island TickEncounter Resource Center, which demonstrates how to safely and effectively treat clothing by soaking it. They also have videos on how to treat other items, such as shoes and hats, using a spray method. If after viewing these, you do not feel comfortable treating your own clothing, you could simply purchase pre-treated items. Either way, the permethrin will be limited to your clothing and will not leave any residual in your yard or garden. As long as your chickens are not exposed to the wet clothing as you are treating it, there should be no risk to them.

raised bed gardenQ: Do you have information on the high yield vegetables to grow in raised beds in Norway/South Paris area in Oxford County?

A: For data on yields (and other characteristics) of various vegetable varieties in Maine, you can look at the variety trials done at Highmoor Farm in Monmouth, just 30 miles east of South Paris. Overall yield comes down to more than variety, but also how intensively you manage your raised beds. Having a soil test done and amending your beds accordingly, as well as proper watering, pruning (if necessary), and pest management — including weeds, diseases, and insects — will all have an impact on what you can expect for yields from any vegetable you decide to plant.

soybeansQ: Do you have a reliable seed viability chart? Are there ideal conditions for storing seeds?

A: Our publication An Introduction to Seed Saving for the Home Gardener by Vegetable Specialist Dr. Mark Hutton, is a great resource for determining some best practices for saving and storing seed. In general, cool and dry are ideal for storage of your saved seeds. There is a chart included for how long you can expect seeds to last, but sprout testing is the best method to determine viability in the planting year.

Q: I started a garden in my small city lot several years ago: some veggies in containers and others in raised beds. I love squash but have had poor results. The butternut grew to baseball size and then quit. Any suggestions? Also, do you have any publications for the backyard gardener?

butternut squashA: Winter squash is generally considered easy to grow, but does require full sun and lots of moisture as fruit are developing. The fertility requirements are also fairly high for winter squash. Have you done a soil test of your raised beds? Do you know your pH? How did you amend your soil prior to planting, or side-dress once the plants started to run? UMaine Extension has many publications for gardeners. You can explore our gardening page or jump right to our publications or videos for resources you can use right now.

Q: This is a two-part question. Part 1: We live in Brunswick, Maine, where our soil is very poor sand. Oddly, after a good soaking, the water will stand on the surface, and after it disappears, the soil is often still dry. How do I address the problem of terrible soil?

Part 2: We built raised-beds with trucked-in soil as a solution to the sand problem, but have fought quack grass ever since. It has taken over the raised beds and we are tired of that battle. We’re prepared to give the whole garden a rest for a year to focus on eradicating the quack, but we don’t want to waste our energies. Should we cover the whole area with heavy weed barrier? A cover crop? Thick wood chip mulch? A sheet of plastic? We’re trying to remain organic in this effort, so prefer to avoid chemical solutions.

Solarizing a garden plot with clear plastic mulch
Solarizing an area with clear plastic mulch. Photo by Marjorie Peronto.

A: Part 1 first: Have you had a soil test done recently? If so, what was your organic matter content? Generally, the addition of organic matter over time can drastically improve soil structure. Rototilling destroys it. It is not a quick fix, but spreading a thin layer of compost each year and allowing the soil biota to incorporate it into the soil will change your native soil and improve drainage and water holding capacity at the same time.

Part 2: Fighting weeds is the number one reason people give up on their home gardens. It is very frustrating! You can solarize the soil in your raised beds, as described in Bulletin #2752, Extending the Gardening Season. Clear plastic, completely covering and tucked in at the edges during the warmest part of the spring and summer can go a long way to solving this problem. You can kill everything in the top six inches (good and bad) if it is done correctly, so be sure to add organic matter (without weed seeds!) back in as soon as you uncover it.

Q: How do I get rid of invasive bittersweet? I have tried pulling up the roots, but it seems that any little bit left behind causes new growth. Is there any kind of treatment that will not harm birds and butterflies or other plants?

Asiatic bittersweet berriesA: Asiatic bittersweet (Celastrus orbiculata) is one of the nastier invasive species that we deal with in Maine. Is is very aggressive, as you have experienced, and difficult to eradicate from a landscape. If you are committed to removing this plant, it will likely take several years. A combination of hand-pulling young plants and cutting the stems of older vines are key. Painting a systemic herbicide (triclopyr or glyphosate) onto the cut stems of vines you cannot pull from the ground will kill the parts of the plant that are below the soil surface. For more information, see UMaine Extension Bulletin #2506, Asiatic Bittersweet from our Maine Invasive Plants series.

Q: Do you have a video that shows how to prune grape vines?

A: Yes we do! Check out Growing Grapes in Maine for everything you need to know, including embedded videos of pruning from our Small Fruit and Vegetable Specialist, Dr. David Handley.

septic leach fieldQ: How many feet away from a septic leach field should a vegetable garden or apple tree be planted? I read on your website that you shouldn’t plant on or near a leach field, but what distance is safe?

A: Trees with “less aggressive” root systems, such as apples, should be planted a minimum of 20 feet from the edge of a leach field. Trees with water-seeking roots such as maple and willow should be at least 50 feet away. A vegetable garden could be a bit closer, but you need to be absolutely sure that the soil you are working in is not part of your leach field, which may contain pathogens that could transfer to your vegetables. Rototilling and other cultivation could also cause costly damage to your leach field, which is the most expensive portion of your septic system. If you can stay 20 feet from the edge, I would recommend that you do.

Q: We use two greenhouses as season extenders. One is approximately 40′ x 20′; the other is 20′ x 15′. The smaller one also houses our chickens (layers) during the winter months, and it was a replacement construction last year, with new soil having been added to the ground. We have a number of problems that have magnified over the last couple of years as we did not know exactly what we were dealing with, and/or how to proceed. First off, I believe we have a problem with ants in both greenhouses, which also means we have aphids. I know we have to get rid of the ants first and I’m told boric acid is a good strategy but I’m concerned with the toxicity for our chickens in the greenhouse which houses them. But then, maybe the chickens will eat the ants, and it won’t be of concern this season?

We also have a problem with our tomato plants. The lower leaves were affected first, appearing to have yellowish spots and eventually turning brown. We were able to harvest plenty of good tomatoes, but by the end of the season, the plants were quite ugly and brown with several spotted tomatoes on the vine. We got rid of the tomato plants at end of the season, but I’m not sure if we need to do anything specific to the soil. Is the problem leaf mold?

hoop houseA: Hoop houses are great for extending the season and preventing many diseases by reducing leaf wetness. They are not without their downsides, though. Re-using the same soil over and over again without regular rain events to flush salts and other minerals from the surface can cause problems. Diseases, once established in the soil, may not be killed by freezing temperatures found just outside the plastic walls. Insects are happy to hang around if it is warm enough as well. In Maine, we count on our cold winters to break the “pest cycle” and allow us to start fresh each spring. The solution to both of your issues is simple, but without knowing much about your property, may be difficult. Hoop houses need to either be moved to new locations or opened up for the winter every few years to allow moisture and cold temperatures to reach the soil underneath and kills diseases and insects. The disease you describe on your tomatoes sounds like early blight, and is soil-borne. You can read more about this disease in Pest Management Fact Sheet #5087, Early Blight of Tomato. If you can, I recommend at least rolling up the sides on both houses for the next month to gain some benefit from the remaining cold. The New England Vegetable Management Guide includes some best practices for hoop house (also called high tunnels) management.

Q: Can I use coffee or coffee grounds in my garden? Can I use coffee for watering my plants or as a fertilizer?

A: We often use coffee grounds as a source of organic matter, but almost always they are added to a compost pile, rather than directly to plants or soil.

Redosier Dogwood flower
Redosier Dogwood (Cornus sericea ssp. sericea). Photo by Mary Ellen (Mel) Harte;

Q: Does UMaine Extension offer seedlings in the spring? I am looking for redosier dogwood. If you do not offer them, where might I find some?

A: UMaine Extension does not have a seedling sale, but many counties have Master Gardener Volunteer (MGV) programs that hold plant sales in May. I recommend contacting your local Extension county office to see if there is an MGV plant sale coming up. You might even be able to put in a request for redosier dogwood now! If you do not have a local plant sale, I recommend one of Maine’s many locally-owned nurseries.

Q: Is it illegal to grow all kinds of currants in Maine because of White Pine Blister Rust? There are varieties deemed “blister rust-resistant,” but I have read that the virus has mutated and become able to infect “resistant” current varieties. What’s the law in Maine?

White Pine Blister Rust
Underside of Jostaberry leaf infected with White Pine Blister Rust.

A: Excellent question and a great idea to ask before importing any plant material! Yes, it remains illegal to grow any variety of currant in southern Maine (and some in northern Maine), regardless of resistance claims. Here is a recent article from Forest Pathologist William Ostroksky, with more details and links.

Ribes Species and White Pine Blister Rust – June 9, 2015

Over the past several years, interest has increased throughout the Northeast in growing and cultivating currants, gooseberries, and other species in the genus Ribes for backyard and commercial fruit production. Stimulated by development of varieties that were either resistant or immune to the white pine blister rust pathogen, Cronartium ribicola, several states, including New York and New Hampshire, have eased the once-standard and universal quarantine of Ribes plants that protected the white pine resource and that had been in place for many decades. Unlike other neighboring states, Maine never changed its Ribes quarantine law, and now that decision has come to work to our advantage. A new strain of the pathogen C. ribicola, identified in late 2010, is now known to be able to infect previously resistant and immune species and cultivars of Ribes.

A study was completed in 2014 by the USDA Forest Service to determine the effects of this new strain of C. ribicola on Ribes and the white pine hosts in New Hampshire. The presence of C. ribicola was confirmed on 17 of the 19 immune or resistant Ribes cultivars screened. The study also reported an 18 percent probability of finding white pine blister rust on pines neighboring black currants that were infected with the new pathogen strain, but only a 2 percent probability of finding the rust on pines neighboring pathogen-free Ribes. The difference was highly significant both statistically and epidemiologically. See the full report.

Results from this study show that the breakdown of resistance in Ribes poses a significant threat to the white pine resource and to cultivated Ribes production. For this reason, all Maine farmers and gardeners need to be aware that the state quarantine prohibiting the culture of European black currants (Ribes nigrum) and all its cultivars throughout the state, and prohibiting European black currants and all other Ribes spp. in the defined quarantine zone, remains in effect. The map and town list of the Maine quarantine areas can be viewed at
White Pine Blister RustQuarantine Area (PDF).

William D. Ostrofsky, Forest Pathologist
Maine Forest Service

Q: I have several rhubarb plants, but this year I was not able to harvest the rhubarb. I just left the plants and never cut it down or anything. At this point, should I just leave them? Should I cut them in the spring? Leave them be? I would appreciate any ideas/advice you may have on rhubarb.

rhubarb growing in the gardenA: Your plants will be just fine, despite being left alone all season. They do not require pruning to stay healthy, though they do put on more vegetative growth if the flower stalks are removed. If they are becoming too large, you might consider dividing them in early spring and removing all flower stalks throughout the summer. Here is some information on dividing rhubarb from University of Minnesota Extension:

The rhubarb plant will produce the next year’s buds at the outer edges of its crown. With each passing year, the plant will become slightly wider, and the center may not produce any new stalks. Like many perennial plants, rhubarb can benefit from division every few years.

Very early in the season, just as new growth is starting, use a clean, sharp shovel to cut the plant in half or in thirds. Remove the divisions to newly prepared planting sites, or give them away. Alternatively, try to dig up the entire plant, and divide it using a sharp knife.

Because rhubarb makes such nutritional demands on the soil, it may be worth moving the plant to a new site every so often, and rotating another crop into the former rhubarb patch.

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