Got questions about gardening 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

Summer 2020 Q&A

Answers are provided by Donna Coffin, Extension Professor, Penobscot & Piscataquis Counties; Caragh Fitzgerald, Associate Extension Professor, Agriculture, UMaine Extension Kennebec County; Kate Garland, Horticultural Professional, UMaine Extension Penobscot County; Pamela Hargest, Horticulture Professional, UMaine Extension Cumberland County; Kathy Hopkins, Extension Educator, UMaine Extension Somerset County; Tori Jackson, Extension Educator: Agriculture and Natural Resources, Rebecca Long, Agriculture and Food System Professional, Oxford County; UMaine Extension Androscoggin and Sagadahoc Counties; Marjorie Peronto, Extension Educator, UMaine Extension Hancock and Washington Counties; Elizabeth Stanley, Horticulture Community Education Assistant, UMaine Extension Knox, Lincoln, and Waldo Counties; Frank Wertheim, Extension Educator, Agriculture/Horticulture, UMaine Extension York County; and Mary Wicklund, Home Horticulture Coordinator, UMaine Extension Cumberland County.

Q. Why are my zucchini leaves turning yellow/brown and dried out?

A. There are several reasons why Zucchini leaves could be yellowing. When this has occurred in my garden in southern Maine, quite frequently the culprit has been the striped cucumber beetle, which in addition to causing root and plant damage, can also transmit diseases such as bacterial wilt, which does cause yellowing and wilting of the leaves and ultimately can kill the vines or set back your yield significantly. 

This University of Minnesota Fact Sheet has some good images of a variety of possible insects and diseases which can cause problems for Zucchini and Squash plants.

You are welcome to please send us a photo which would help us to more specifically diagnose the problem for you and be able to make the appropriate recommendations.

Q. I have broccoli plants in three different locations. All of them have very large green leaves and no heads, just some tiny florets. What is going on?

A. It sounds as though your broccoli plants are doing what is called “buttoning.”  It’s typically a response to stress that occurred early in the plant’s development. It might have been cold weather, dry soils, overly-mature transplants, insufficient nutrients, or other conditions. See, Buttoning in broccoli and cauliflower, from the University of California.

Q. I live in Falmouth. This year I see a lot of chipmunks/tiny squirrels in my garden, that is creating a havoc by digging the raised beds. I have tried putting a chicken fence around the raised beds, and now I have built fence around all my raised beds, and still they are unstoppable. My tomato plants are flowering now, and I am worried about how to save the tomatoes when the fruit is set.

I obviously do NOT want to harm them in any way, but want to repel them and save my plants/fruits. Can you suggest an option for this please?

A. This seems to be a banner year for chipmunk activity as last year was a big acorn year. For control strategies we recommend you contact the USDA Wildlife Services office in Augusta at:

Phone: 207.629.5181

USDA Wildlife Services
79 Leighton Rd., Suite 12
Augusta ME, 04330

Stalk in meadowQ. This odd plant has started showing up in a “meadow to be” area that we are not mowing. It has a long, segmented stalk, some about three feet high for now. I wasn’t able to pull out the root or rhizome, the plant broke off at the base. Could you help me identify this and should I be concerned? See photo.

A. The plant in the photo is common valerian (Valeriana officinalis). It is a non-native species, likely escaped from cultivation, and is listed in Maine as having the potential to be invasive. There is a valerian native to Maine (Valeriana uliginosa) but it has several distinguishing features including fewer leaflets on the leaf blades on the stem.

Q. I started an apple tree from seed and it’s now planted in the front yard about six feet tall. It has a double trunk, and I’ve held off pruning the shorter one off so as to keep maximum leaves exposed in order to support the root stock, but at some point am going to have to reduce it to one main trunk.

When will my tree reach sufficient maturity to cut it back to one trunk?

A. Reshaping your tree is best done while it is small, and your tree is large enough to prune it to one main trunk at its current size. The ideal time to prune fruit trees is late winter into early spring. However, summer pruning can also be performed, although severe pruning may weaken the tree. Therefore, the majority of pruning should be done during the winter or early spring.

As your tree has been started from a seed, it may grow quite large. I would suggest planning for giving it plenty of space to grow, up to 20 feet. 

Q. I have never had such a huge problem with moles in my vegetables. They undermine the roots with their tunnels. I stamp down tunnels every day, but I have vegetable, herb and flower gardens and I can’t even make a difference in the vegetable garden. Spinach crop was probably 50% of normal. I have set snap traps in the tunnels and caught two moles, two shrews and one white footed mouse. The damage continues unabated. I would rather exclude or repel than kill, but how? And if I must kill, what’s the most humane way?

A. This page, Living With Wildlife, from the Department of Inland Fisheries and Wildlife has an extensive rundown of mole control measures. For non-lethal control measures, exclusion is the best option but this could be costly depending on the size of your garden. Raised beds can be constructed with wire underneath. While that page lists a number of lethal control measures, this one, Controlling Damage From Moles and Voles, from Alabama Extension also provides good visual references for the various types of traps. Another good resource is the Wildlife Services division of the USDA APHIS, contact info is listed on their website.

Q. I think I have an infestation of leafhoppers. Is there a safe, organic way to control them? I use the salad greens to feed my chickens and am hoping for a method that doesn’t require washing before consumption.

A. The first step would be to confirm that what you have is indeed leafhoppers. They are small, green, wedge shaped insects that tend to fly up when a plant is shaken or disturbed. Sweep nets can also be used to catch them. Because leafhoppers suck out plant juices, damage will appear as yellowing, curling and stunting of leaves.

Control options:

  • Row covers can be used to protect plants but must be removed at flowering.
  • Keep weeds down, especially perennial weeds, as they can harbor leafhopper eggs.
  • Because there are many natural enemies that help control leafhoppers, be very cautious with any chemical control options so you are not impacting beneficial predators.

From University of Maryland Extension, Potato Leafhopper, Vegetables: “For large numbers, use botanical insecticides such as insecticidal soap, horticultural oil, neem, pyrethrum, or combinations thereof. Spray early in the day when insects are sluggish. Thoroughly wet leaf undersides. Apply repeatedly for large populations.”

Make sure your pesticide is labeled for the pest and crop you plan to spray it on. Follow label instructions including any pre-harvest interval (the time between when you spray and when you can harvest) for yourself and your chickens.

MMountain Ash Sawfly larvaeQ. Our back yard mountain ash has many leaves stripped down to the center vein. Many of the wild phlox have suffered the same fate. The photo shows the damage to one branch, and the caterpillars doing the work. What are our safe alternatives to protect this small tree?

A. The mountain ash has Mountain Ash Sawfly larvae. They are not caterpillars, so some products like Bt will not work on them.

Here’s a good fact sheet about the insect, its life cycle and how you can control it.
Mountain Ash Sawfly from the Maine Forest Service.

One method not mentioned, if the tree is close to a hose, you can blast them off. This disrupts their feeding and knocks them on the ground where the birds will feast on them.

Q. I believe my young grafted Baldwin has fire blight. What should I do for treatment?

A. Fire blight is a possibility, and Baldwin is particularly susceptible to it. It would be best to confirm the diagnosis with UMaine Extension’s Plant Disease Diagnostic Lab. Photos might be sufficient, email them to Dr. Alicyn Smart,  Be sure to include your name, phone number, business name, county, host plant, problem, date when symptoms were noted and good, in-focus images. 

If it is fire blight, management recommendations are described in this Fire blight outbreaks article from UNH. It includes information about how to prune out infected branches at this time of year and how to sterilize tools. Be aware that the fungicide mentioned for consideration (Cueva) is only labeled for commercial use, not home garden use. 

Q. Which compost mix would you recommend for shrubs and perennials in very sandy loam that hasn’t ever had any amendments? Would straight composted cow/horse manure be best or half manure half green waste?

A. Building your sandy soil’s organic matter by adding compost is a very good idea to help the soil hold water and retain nutrients. Compost from either source (horse or composted greens) would be equally fine. The only risk, if you are composting your own horse manure ((vs. commercially purchased compost) is that some weed seeds will likely survive the compost process and you could introduce some weeds you will later have to battle. With commercial compost or compost that is well heated and turned during the process would kill off any weed seeds. 

Here is a link to our bulletin on Home Composting, and for more resources, a link to our Master Gardener Manual chapter on Composting

VincaQ. I have been establishing native plants on our property for a few years now. In the past, I have planted invasive Vinca which is spreading to the woods. Very time consuming to control! I recently found some Pyrola Minor growing among the Vinca. I’m thinking the best course of action is to try to keep the Vinca thin in that area. I’m afraid to pull it all out as the Pyrola seems shallow rooted. Suggestions? I live in Durham and was surprised to see this plant. I thought it was only found further north.

A. I have also experienced Vinca, which I planted in my garden many years ago, escaping into wild non landscaped areas. It is not listed on the Maine Invasive Plants web page, however, as you have noticed it does have invasive tendencies and is of concern. Your question about how to thin it with another plant you are trying to protect growing near it is very tricky. You are correct, in that it would be hard to pull without disturbing the plants within its vicinity. Vinca spreads through trailing vines/stems which root as they touch the ground. You could try to very carefully lift up and cut off the vines to prevent them from rooting and spreading further.

This would only be a short term solution as the Vinca will resprout new trailing vines and you would have to continue this process. Using any herbicide would be extremely difficult without also taking out the plants growing near it so I would not recommend that. I am afraid I don’t have a very good answer for you besides keeping it from trailing in order to slow down its spread, but it does want to naturalize and will be persistent. 

Browning leavesQ. I have bush green beans and pole beans in my garden. The leaves on both types are curling and yellowing. Do you know what is causing that and how to correct it? Attached is a photo of a pole bean plant taken shortly after three days of rain totaling about 2.5″. The problem started prior to the rainfall event. I have planted similar type beans in my garden before and they thrived, looking much better than these.

A. From your picture, it looks like “hopperburn,” the term for damage caused by leafhoppers. Leafhoppers are flightly so if you brush past the plant, you may notice small insects flying away. From our fact sheet on sucking insects: “Leafhoppers are small, green, wedge shaped insects that attack many garden, forage and fruit crops. They suck out plant juices causing yellowing, leaf-curling and stunting. They also transmit several disease organisms, especially associated with yellows. Use pyrethrins or carbaryl (Sevin) as a control.” Make sure any pesticides are labeled for your specific crop and read and follow label directions. Row cover can be used to protect young plants until flowering, although this may be less effective if the insects are already present.

Q. I am doing raised beds for the first time this summer. I have Eureka and Marketplace cucumbers and am wondering if I need to stake or trellis them?

A. Although the plants can be allowed to grow on the ground (raised bed or not), trellising will not only save space but will help provide longer and straighter cucumbers. Growing upright will make it easier to harvest and also keep the cucumbers cleaner.

I did see reference to the Eureka variety with recommendations to trellis. I didn’t find Marketplace but did find a couple of Marketmore varieties; they also recommend trellising. Unless you grow a bush variety of cucumber, trellising is a good idea.

To learn more, visit the Cornell University website about growing cucumbers, which you might find helpful.

Q. Unfortunately, it seems our hemlocks have been infested with woolly Adelgid this year. We pride ourselves on not using chemical fertilizers and pesticides in the yard. I’ve read that the most effective treatment is to use a systemic insecticide and am very hesitant to do so. It seems another alternative is to use a horticultural oil or insecticidal soap, although I’m not confident we can get it applied high enough up the tree with a pump sprayer. Do you have any experience with any of these products? If we give the horticultural oil or insecticidal soap a try and it doesn’t work have we lost valuable time with the hemlocks? Are the horticultural oil and insecticidal soap used in conjunction? Any advice you have is greatly appreciated.

A. I’m sorry your trees are infested. The Maine Forest Service is tracking HWA in Maine and would like you to report it to them.

For more information about the insect and how to control it, visit this HWA fact sheet (PDF).

Crown vetchQ. I have about an acre and a half meadow behind my house on MDI with a stream at the bottom. Sadly it has become invaded by crown vetch. I didn’t plant it! It may have been here when we bought the place and I didn’t notice it right away but it is taking over now. I’ve read the best way to control is to just keep mowing it. Sadly, that mows the native grasses and wildflowers, too. Is there another solution? If it has to be mowed, when and how often? Do you think it would work to just mow the upper parts where it is? It has not spread to the lower section, which has pretty dense grasses.

A. I recommend mowing in this situation. While it’s going to impact the success of some of the wildflower species you’re aiming to keep and wildlife habitat this year, I think it’s an important short-term compromise to make in order to have the best long-term success. Use a grass catcher to try to keep the seeds from dropping and reseeding itself. A couple years of mowing the vetch when it’s in flower should help get it under control. Also, nitrogen fertilizer would encourage the grass to start out-competing the vetch. A soil test to determine other nutrient needs for the grass is good practice.

Q. Is it safe to eat strawberries that have been irrigated with stagnant water?

A. Our small fruit specialist says, “If they were irrigated via trickle or drip irrigation, there should be no problem. If they were overhead irrigated and more than two days have passed, there should be no problem. If they were overhead irrigated and picked shortly after, they could be rinsed and allowed to dry, and there should be no problem. The farmer should be getting the water tested for problems if they are going to use surface water, overhead, near harvest.”

Q. We have been offered a couple of Selaginella lepidophylla (resurrection plant or false rose of Jericho). We are wondering if we plant the two of them, will they become an “invasive species” that can’t be/would be difficult to control?

A. It’s always a good idea to confirm that an exotic plant won’t become invasive before planting it. The state of Maine has a comprehensive list of invasive and potentially invasive plants that can be a helpful guide for you. It’s very unlikely that Selaginella lepidophylla would become invasive here in Maine for a few reasons. It doesn’t appear to be hardy enough to withstand our cold winters and therefore should be treated as an annual. Also, it is typically found in a very niche habitat of the desert, which is very different from the climate we have here in Maine. 

Q. We live in South Portland and there is a drought at the moment. How often should we water our vegetable garden?

A. Ideally, 1.25 to 1.5 inches of rain per week is enough for most gardens. A rain gauge can help you decide when to water.

It’s good to get water down to 5-6 inches of soil depth, but there are a lot of factors at play: your soil type (sand or clay), how much organic matter your soil has in it, what growth stage your plants are in, whether you have raised beds, whether your garden is mulched, how much sun and wind there is, etc.

When watering, it’s better to water deeply but less often; this encourages plant roots to move further down into the soil. Since roots need oxygen, never keep your soil saturated.

Another important tip is to water at the base of the plant (rather than on the leaves) to prevent disease. This is especially important for tomatoes.

How to Water your Garden is a new video we’ve just produced that will give you more info and strategies for dealing with this drought.

Q. I compost my tomato patch (6×10) every fall with two wheelbarrows of horse manure. I bury deep and space my plants 20 inches apart. Every year my plants grow “leggy” (tall and narrow stems), with frail vines, unable to support a good yield, despite adequate water, weeding, and TLC. Please advise.

A. The soil is likely the key factor, but it might also be due to limited light. Tomatoes and other fruiting crops need at least 8 hours of full sunlight for optimal growth and production. Plants growing in insufficient light will develop just as you described: thin, leggy stems, and very little fruit. 

Aged animal manures are a common source of organic matter in gardens. While organic matter plays an important role in improving soil structure and the capacity for the soil to serve as a “bank” for nutrients, it is not a potent and immediate source of nutrients compared to traditional garden fertilizers. Annually adding aged manure or compost to mineral soil is a good practice, but it’s important to apply in moderation. Six cubic feet per 1,000 square feet (the equivalent of six 1-cubic-foot bags over a 20′ x 50′ area) applied in the fall is a good target application rate. Applying fully composted manure at the same rate in the spring is also a good practice. It’s possible to add too much organic matter to the soil. Overapplication can actually decrease production because the biological activity can deplete the soil oxygen levels. 

To regroup, I would start by having your soil tested (midseason is still a good time to soil test) to get important information about organic matter content, nutrient levels and pH as well as whether you have lead in the soil. Request a soil test kit here. Follow the recommendations on the soil test results to make targeted adjustments to create optimal growing conditions. 

Also, it’s best to not grow tomatoes in the same location year after year. Disease and pest pressure can build when any crop is repeatedly planted in the same site. In landscapes where you don’t have an alternative site for crop rotation, consider alternating what you plan to buy at the farmers market and what you plan to grow. Here’s more information from Penn State Extension, on why it’s important to rotate crops based on plant families, Plant Rotation in the Garden Based on Plant Families.

Q. I just bought an astilbe and a brunnera to plant. Now I’m told it’s not the best time to plant them. Is that so? I may have to plant them anyway within the next couple weeks and I have never planted a perennial before. I plan to mix Bumper Crop with the soil. What do I need to remember in terms of “how-to”?

A. It will be best to plant your brunnera and astilbe rather than leaving them in the pot. Here are some helpful hints for planting:

  • Dig a hole that’s at least twice as wide (but not deeper) than the plant’s roots.
  • If it’s a new garden, think about testing your soil so you know what the pH and nutrients are like. (You can plant now and test later.)
  • Moisten the hole, since the surrounding soil is probably very dry right now. Let it drain out.
  • Amend the soil with no more than 20% bagged compost (like your bag of Bumper Crop) and mix well into the native soil. (Do not add fertilizer, which can damage the roots.)
  • Tease the roots out if they’re bound or circling in the pot. If they’re terribly pot bound, you can cut vertical slits to fluff them out.
  • Gently place the roots horizontally into the hole, back filling as you go.
  • Carefully press the soil around the plant and create a small ring to dam and hold water.
  • Water deeply. During dry spells, perhaps every three days. (NOT DAILY.) The plant needs a chance to partially dry between watering. (Roots need oxygen.)
  • 2″ of shredded bark mulch can help the soil hold moisture and prevent the roots from getting too hot. Don’t smother the stem or crown of the plant.
  • If planted well, you won’t need to add fertilizer. (In the first year, you want to encourage root growth, not top growth.) If you choose to fertilize, dilute well and don’t add any after mid-summer so the plants can go dormant before winter.
  • After Thanksgiving, protect the plants for the first winter with a few balsam fir boughs. Remove them after daffodils emerge.

The Cornell Growing Guides have great info about most perennials and annuals.

Brunnera is a spring flowering plant, and likes shade and moist organic soil. Like most spring ephemerals, it naturally goes dormant around now, so don’t be worried when it starts to turn brown. (That’s why people plant them behind summer flowering plants.)

Astilbe comes in two groups with many cultivars.

If you’re interested in growing fruits, vegetables, and trees and shrubs for the Maine Landscape, bookmark our Garden & Yard website.

Q. Chipmunks are being pests in my garden, any suggestions? Other than hardware cloth underground.

A. Their numbers are high this season, and people are home noticing them more. Unfortunately, there’s no one silver bullet for keeping them from harming your garden. There are some good strategies for reducing their number in this fact sheet from the University of New Hampshire, Chipmunks in the Garden.

Q. Can I grow fruit and vegetables in the same garden?

A. Yes, you can grow all sorts of things in the same garden. Vegetables and fruits (especially small fruits like high bush blueberry, strawberry, etc.), vegetables and flowers, vegetables, and perennial vegetables (like asparagus, rhubarb, etc.). Much depends on the size of your garden and how you lay it out to facilitate the soil needs for the different plants, and the ability to rotate some crops around in successive years. Keep in mind that most fruits and vegetables need 6-8 hours of full sun. Your garden should be where you can visit it each day (close to your home) and easy to tend and water.

We have a series of Victory Garden videos for beginner gardeners. So far there are 6, starting with Vegetable Gardening: Where to Begin. The second one is about Planning your Garden.

Spots on Iris leavesQ. I am looking for a solution to a leaf spot problem on my bearded irises. The foliage starts out green and beautiful in the spring, but gradually develops yellow and brown spots, so that by the fall, almost all the leaves are heavily spotted or brown. I am hoping to find a less toxic option than the Ortho product (Garden Disease Control).

A. I ran this by our plant disease diagnostician and she’d like to see a sample. Please follow the directions on this website

Q. I am considering a peach tree for my garden/yard in Durham. I have mature pear trees and several 3-year-old apple trees in the vicinity of the planned location for peach. Do I need more than one tree? Can you recommend a variety? I am interested in flavor of course, but hardiness, disease resistance, and longevity trump flavor.

A. Growing in Durham will be relatively easy compared to more northern parts of Maine, where flower buds might get late spring frosts. 

Most peach varieties are self-fruitful and do not require another variety for cross-pollination. The exceptions to this are JH Hale, Indian, and Indian Blood. Self-fruitful trees can be expected to produce abundantly when planted alone.

I think most would agree that Redhaven is the best tasting hardy peach. The pit separates from the flesh when ripe, so it’s much easier to eat and process than other varieties. Its flower display is not as fancy as others, but the fruit is very pretty when ripe.

Bare-root trees should be ordered in January or February to avoid missing the deadline (and supply).

Here’s more information about varieties, planting, pruning and care:

Q. My annuals (cleome, cosmos, morning glory, zinnias, sunflowers) are making very little growth and look stunted. I feel that it may be due to an over-application of bark mulch over a number of years. Or could they be suffering from high acid content of soil? Or the drought conditions, though I water thoroughly on a regular basis? One or all of above? How does one change the pH to make soil of established annuals more alkaline? My potted zinnias are hardly growing, although looking healthy. I have used Espoma Flower-tone 3-4-5 once on all of the deck pots and in the ground. Using Neptune’s fish emulsion when watering deck plants.

I have a Sungold tomato in the ground where one thrived last summer. I now remember that perhaps one does not plant tomato in the same spot? It is doing fairly well considering the growing conditions here on the coast here in Boothbay Harbor.

A. It’s hard to know for sure what the issue might be with your annuals; it could be a variety of factors. I wouldn’t worry just yet, it can take some time for your annuals to become established. Bark mulch doesn’t need to be applied every year, in fact, every other year or even less frequent (depending on the quantity) should work fine. I don’t think this alone would have caused stunted growth on your plants. When did you plant your annuals outside? Were they directly sown or planted as seedlings? It sounds like you are watering them well, which is important for establishment. Keep in mind that it is important to water them deeply, wetting the top 5-6” of the soil. We just launched this How to Water Your Garden video as part of our Victory Garden Series that can help guide your watering practices. 

I’d recommend that you have a soil test completed for your garden; you never want to amend the pH of your soil without knowing what your current pH level is in your soil. The standard soil test will also give you a good read on what the current macro and micronutrients are in your soil. You’ll receive specific instructions on how to amend your soil to achieve optimum nutrient and pH levels for growing your annuals. You can request a soil test kit to be mailed directly to your house by completing this online form

You also want to be very careful not to over-fertilize your plants because that can result in a high concentration of salt which can damage the roots of your plants if there are excessive applications, especially in containers. Typically, gardeners can apply a general-purpose fertilizer just before planting, then again as a side dressing 4-6 weeks later. 

It’s always a good idea to rotate your crops especially plants that belong to the Solanaceae family, such as tomatoes. It’s probably fine if you planted your tomato in the same spot as last year, just try to rotate it to a new location the following year.


Q. My question doesn’t concern my garden, but I am trying to identify a bush growing wild under the pine trees.

A. Thank you for the great photo! It looks like you have our native Honeysuckle, Lonicera canadensis

Q. I have a Rose of Sharon in need of pruning. Can you tell me the best time to prune? I just read two seemingly informed articles with entirely contradictory advice, one saying prune in spring or right after the flowers drop, but not in late fall or winter, and the other saying the best time is in late fall or winter.

A. Pruning out dead or damaged branches can be done at any time. If you are pruning it for shape or size and are thinking about how it will flower, then it should be in late Winter or early Spring. For more information, see The Pruning Calendar.

Most shrubs that flower after the end of June produce their flower buds early in the current season, on new wood. These include buddleia, clematis, clethra, rose of Sharon, hydrangea, potentilla, and rose. These shrubs should be pruned in winter or early spring, just before the season’s growth begins.

Here is a wide range of information about growing this beautiful shrub.

Apple Cedar RustQ. This question is about the flowering crab in my front yard. After beautifully flowering in the spring, its leaves have started turning yellow and drop prematurely. What is causing this and what can I do to save this beautiful tree? It’s been there since Dad planted it years ago and I can’t bear to see it looking so bad. I am located in southern Maine.

A. Our Plant Pathologist got back to me in regards to your photos. She has confirmed that you have Apple Cedar Rust. She also said you are probably not seeing any sporulation because it’s too dry, but it will eventually occur. 

The other host for Apple Cedar Rust is a plant from the Cupressaceae family (red cedar and juniper). If you are able to tolerate the leaf spots, they don’t tend to cause significant damage to crabapple trees. You can also identify and cut down any red cedar and juniper plants within a few hundred yards of your crabapple if that’s reasonable to do so. Another simple measure you can take is to inspect any juniper and red cedar trees in the winter for galls and remove them before they turn orange and become gelatinous. 

Here is more information about Cedar Apple Rust from the University of Minnesota Extension. 

lupinesQ. Something is eating my lupine seeds. In one of my three beds, all the lower of the lupine flower stalk is being stripped. Chipmunks, birds, or something else?

A. Is it possible that they have aphids? It’s not quite clear in your photos, but it seems possible and that the leaves still visible are suffering. Lupines are healthiest in full sun, cool temperatures, and well-drained soils. Recent higher temps may contribute to the problem but aphids are a very common pest on lupines.  

If you are seeing aphids, a strong jet of water should wash them off the plant, but you may need to repeat that if they return. Here is information about aphids from the University of Maryland Extension.

Q. I gave my clematis a bad haircut at the start of the season, accidentally cutting off live stems. Similarly, last summer, my baptisia got huge and bent over after a hard rain and the advice from you guys was to cut it back.

This year, both plants have come back, but not nearly as robust and full as before. My clematis is about 1/2 of what it was at this time last year, and the baptisia is also quite small, about 1/3 of the size that it was. Both have very few flowers.

Is this to be expected when you generously cut back these two perennials? Can I expect that, over the next few years, they can and will grow back to their big bushy state, or will they forever be sort of small? Is there anything I can do to encourage growth?

A. Clematis: Once established, clematis is long-lived if kept watered during drought, and top dressed in the spring with some compost. Mulch or an overstory of shallow-rooted herbaceous plants (columbine, rose campion, etc.) can keep their roots cool while the flowering vine is in full sun. Most important, clematis come in three types, each pruned differently to keep them healthy and blooming: A, B & C (or 1, 2 & 3).

  • A: Earliest clematis to bloom. Flowers on last season’s wood. Prune minimally (just dead stems). If more is needed, wait until the plant finishes flowering. New growth will then have enough time to grow flower buds for next year. Examples in this group: Clematis alpina, C. macropetala, and their cultivars.
  • B: Flowers on current and last year’s wood. Stems from last season’s wood produce heavily in late spring, followed by a lighter bloom in late summer on new wood. In early spring, only prune dead stems. After the spring flowers fade, the stems that contained those flowers can be shortened. This group is the most difficult to prune, because the vines bloom on old and new wood.  Adjust timing of pruning/cleanup after observing the flowering during the course of a growing season. Examples: Clematis florida and its cultivars, C. ‘Nelly Moser’, C. ‘Niobe’, C. ‘The President’.
  • C: Flowers on new (current year’s) wood, and the simplest of the three pruning types. Bloom in late summer or early fall. Early spring: cut back all stems to buds that are within 12 to 18 inches of the ground. Then let the plant go to town. Examples: Clematis terniflora (sweet autumn clematis), C. ‘Gipsy Queen’, C. ‘Jackmanii’, C. ‘Ville de Lyon’.

If an established clematis is pruned hard or at the wrong time, it will survive. The plant will just flower less, or at a different time than usual. If you’re unsure of the species/cultivar you have, observe its flowering over a full season. After that, you should be able to assign a pruning group and adjust pruning/fall clean-up accordingly. You can sometimes ID the cultivars from catalogs, too.

Baptisia: This is a much more straight-forward plant than clematis! This shrub-like herbaceous perennial can last for years and thrives on neglect since it has very deep roots and makes its own nitrogen. Some people will set up a peony ring to prevent damage during hard rains. (It’s hard to prop up after the fact.) My guess is that it was weakened because it lost some photosynthetic time last season when it was cut back. To nurture it this season, give it deep watering once a week during dry periods, top dress with some compost, keep weeds at bay, and take out any dead material from the center. Avoid fertilizing after mid-summer so it can slowly go dormant before winter. Hopefully, it will catch up and produce flowers next season.

Q. My new blueberry bushes got hit by frost. Will they survive?

A. If your blueberry plants were planted with good, well-drained soil (with the correct pH and fertility), mulched, and given 2″ of water per week, the plants themselves should be okay and continue to grow.

If the flowers were frosted, the fruit may be damaged. In the first two years, it’s best to remove all flowers so that energy is expended on roots.

If the leaves were frosted and distorted, take extra care of the plants. Make sure they have adequate water during dry spells (but never keep them saturated), and avoid extra fertility after midsummer so the plants go slowly dormant before winter.

Here’s more about planting and care: Growing High Bush Blueberries.

Q. Having difficulty with bearberry. Doesn’t seem to thrive in gardens in Seal Harbor. Any advice? What medium should be used to plant bearberry?

A. It would be very helpful to have more info.

  • How long ago was the bearberry planted?
  • What percentage of the overall planting is affected?
  • What is the pH of your soil? (Have you had your soil tested?) Bearberry is fussy about pH: 4.5 – 5.5, similar to wild blueberries.
  • During drought, has it been watered? Even though it likes dry, well drained soil, it needs water, especially to get established.
  • Has it been fertilized? Fertilizing after mid-summer can prevent it from going dormant before winter, resulting in winterkill.
  • Is it mulched? Sometimes the plant won’t send out roots in mulch.
  • What do the roots look like? White and healthy? Dark and mushy?
  • Can you send a photo or two? One of the general planting, and a close up of the plant.

Q. How do I treat sunscald on my peach tree?

A. At this point, you’ll want to trim off any excess bark or prune out any dead branches as a result of sunscald. Sunscald is more common on young trees and a variety of deciduous trees that naturally have thin bark. White tree wraps should be used in the winter for the first several years until the bark thickens. Just be sure to remove the wrap once the night temperatures are above freezing. Also, keep in mind that you want to avoid fertilizing in the late summer or fall because that will encourage new growth at a time when your tree is supposed to prepare for dormancy.

Here is more information about Frost Cracks and Sunscald on Trees from UConn Extension. 

Swiss chardQ. My Swiss chard looked lovely until one morning I went out and discovered tan patches on the leaves. Now, two weeks later, the leaves mostly look dry and dying. I’m attaching a photo. What causes this, and what can I do about it? Is there an organic solution, and can I save my Swiss chard this season or should I just pull it out?

A. We suspect you may have spinach leaf miner. Is there any way you could send me a few more photos of your Swiss chard leaves? It’s a little difficult to identify from the photo you submitted.

Q. I am wrestling with goutweed that has spread next to our wooded stream area and came across this vigorous growth (photos A and B), at the edge of the goutweed area. But also not far from another taller plant that looks like it (photo C). I’m hoping that what is in photos A and B is not goutweed, but the other plant. Can you tell from the photos, and if it’s not, what is the plant in photo C?

A. Unfortunately, I think A and B are both goutweed.

Photo C is sambucus racemosa.

To be sure, remove a leaf and see if it has the same distinct goutweed smell. That’s one of my quick ID tricks with that plant.  

Q. I have a weeding job and there are substantial patches of horsetail in the perennial beds. What would you suggest? I know eradication is tough, but are there ways to keep it contained with our chemicals?

A. Horsetail (Equisetum) is an ancient native plant that many gardeners struggle to control due to its underground rhizome system. I’m afraid there is no easy answer for how to manage Horsetail. You can dig this plant up, just be sure to dig up as much of the roots as possible. If the Horsetail is established, you’ll likely need to continue this practice for a few years before you can successfully eradicate it. Persistence is key here. Horsetail thrives in wet conditions, so if you are able to improve the drainage in the perennial beds that can also help. 

There are not many herbicide options for controlling Horsetail and the effectiveness of such an application is questionable. For more information, check out The Ancient Horsetail (PDF) from Purdue University and Equisetum: Biology and Management from Iowa State University.

Q. I have a small Portland yard that I’ve been slowly working on to create an ecological landscape.  I’m sure there’s a lot I’m missing, but I’m not sure if I should ask for someone to take a look to get advice, or if there are example gardens I should seek out. I’ve found the Portland Pollinator Habitat Map, but many of those gardens look more like traditional ornamental gardens to me, where I would be more interested in seeing residential gardens that mimic the look and function of nature.

A. It’s great to hear of more folks transitioning to natural-looking landscapes. Your situation is a perfect fit for our NEW garden mentor program. Click here to learn more and sign up for a mentor. Our local Master Gardener Volunteer coordinator will match you with a Master Gardener who has expertise in the gardening topics you’re interested in. Our Master Gardeners are a terrific resource and are eager to help. 

Butternut squash leavesQ. Why are my butternut squash leaves turning yellow? They were planted 10 days ago. Onions were in this bed last year.

A. It’s tough to say for sure because I cannot seem to zoom in on the photo to get a good look, but it seems to be showing typical transplant shock symptoms. In a well-sited vegetable garden (full sun with good drainage), it should come through just fine if you provide it with a deep watering twice a week. I would also give it a slight nitrogen boost by putting a very small amount (1tsp) of bloodmeal scratched into the area around the plant (once).

You might want to consider mulching with straw to reduce weed competition and maintain even soil moisture. If you have row cover, this is a good time to cover your young plants to keep out the cucumber beetles. Be sure to remove the row cover when you see both male and female flowers.

Q. This happened just this morning. This weekend, I transplanted two astilbe plants from one garden to another. I water them early in the morning; went out at 6:00 AM to turn on the slow-drip hose and returned at 7:30 to move the hose. At this time, the plant had been dug up, torn apart, a hole about 6-8 inches deep, and no evidence of eating of the plant. The two other transplanted plants were left undisturbed, just three feet away. I have MANY chipmunks, but this had to have been done by something larger. Raccoon? Skunk? And for what? Grubs? Should I replant?

A. If you used an organic fertilizer with bone meal, blood meal or fish emulsion, it may have attracted any number of omnivores: skunk, raccoon, fox, even a cat or dog. 

Any of those animals may also have found a beetle, grub, chipmunk or vole in the area and dug it up in pursuit.

Q. I have one greengage plum, and see curculio damage on fruitlets already. How best to control? It’s a small young tree. Pick off damaged fruits? Put a tarp under to collect drops? Other ideas? Both? I don’t have a sprayer for Surround but do have one I have used for Bt. Holds 2 gallons.

A. Sorry about your plum curculio. It’s very common in Maine.

Are you using a standard fruit tree spray in the orchard? Because of the smorgasbord of fruit trees, it may be a good measure.

This and other pest info is in our Growing Fruit Trees in Maine resource under Insect Pests.

A two-gallon sprayer will work well for most liquid sprays. Be sure to rinse the container well before and after use and follow label directions.

If you’re interested in using Surround, here’s the Label with mixing instructions.

Q. Where’s a good source for salt hay near Freeport, ME?

A. I’m not aware of businesses near Freeport that sell salt marsh hay, you’d be better off looking for this product in coastal areas of Massachusetts, New Hampshire, and very Southern Maine. The only business I know that carries this product in Southern Maine is Wallingford Farm in Kennebunk (no endorsement intended), but I have not purchased salt marsh hay from them myself so I can’t attest to the quality. Have you tried contacting your local nurseries?

Q. I am looking for several fairly low growing shrubs, that will tolerate shade and preferably flower and attract birds. I want to separate my planned shade garden from my shady wilderness.

A. I would suggest going with a Viburnum for your site, especially if you are interested in attracting birds and other wildlife. Maple-leaf Viburnum (Viburnum acerifolium) is a versatile plant that can tolerate moist to dry conditions and thrives in the shade, it gets to be about 3-6’ in height. 

Here are some other options:

  • Hobblebush (Viburnum lantanoides): 3-10’, moist
  • Wild-raisin (Viburnum nudum var. cassinoides): 6-12’, wet to moderately dry
  • Rhodora (Rhododendron canadense): 3-4’, wet/moist
  • Bush Honeysuckle (Diervilla lonicera): 3-4’, medium dry

You can find more plant lists in our Plants for the Maine Landscape chapter of our Maine Master Gardener Volunteer Manual.

Q. What material should I use to cover my blueberry bushes so birds will not eat the berries but also shall not be trapped (no net)?

A. A good quality net that’s elevated above the bushes should not ensnare birds if done correctly.

From our publication Growing Highbush Blueberries:

“Birds are typically the most serious pests of blueberries. Covering the plants with netting is the most effective control. Plastic or cloth netting is available through garden supply dealers. It is best to use a post and wire frame to support the netting over the plants. This will provide the best protection of the fruit and prolong the usable life of the netting. Drape the netting over the frame just as the first berries begin to turn blue. Be sure the edge of the netting is weighted or staked to the ground to prevent birds from getting under. Remove the netting as soon as all harvesting is complete, and store it in a cool, dry place. This will prolong its useful life.”

horse tailQ: We have an aggressive weed that I believe is called “horsetail.” It is growing and spreading in my flower garden, vegetable garden, and all around the “rain garden” (created by the contractor as part of the subdivision plan). I have also noticed it growing along the main road. It appears to be quite invasive. We have tried pulling it up, digging it up, and smothering it. Nothing seems to help. Is there anything I can do to eliminate or reduce it?

A: Horsetail (Equisetum) is an ancient native plant that many gardeners struggle to control due to its underground rhizome system. I’m afraid there is no easy answer for how to manage Horsetail. All of the practices you mentioned, pulling/digging it up and smothering it with help, but it’ll take time. You’ll likely need to continue this practice for a few years before you can successfully eradicate this plant from an area. Persistence is important when handling horsetail because of its extensive root system. Horsetail thrives in wet conditions, so if you are able to improve the drainage in the flower and vegetable gardens that can also help. 

There are not many herbicide options for controlling Horsetail and the effectiveness of such an application is questionable. For more information, check out The Ancient Horsetail (PDF) from Purdue University and Equisetum: Biology and Management from Iowa State University.

Fruit tee leafQ: I planted a fruit tree about 12 years ago; I was told it was a pear. I was never told I needed to have two, so I could get fruit. I would like to add another one in the hope I’ll get fruit someday. Can you tell me what kind it may be, please?

A: Unfortunately, it’s not possible to ID the variety from the leaves.

There are two types of pears, Asian and European. Be sure you choose a pollinator from the same type and a variety that has the same bloom time.

Here’s info from our publication Growing Fruit Trees in Maine.

Yes, many pears are “self-unfruitful” and need another variety nearby for pollination.

Magness, Luscious and Gourmet pears are sterile and will not pollinate other pears. Seckel and Bartlett will not pollinate each other. (If you grow these two varieties, a third will be needed.) Comice, Bartlett, and Flemish Beauty are partially self-fruitful. It may be best to plant two different trees 20 feet from your existing tree since you don’t know the variety of the one you have. Bosc is known to be a good pollinator.

Ask the Expert Q&A Archives