Maine Home Garden News — June 2020

In This Issue:

June Is the Month to . . .

By Ann Marie Bartoo, Master Gardener Volunteer, 2014, and Kate Garland, Horticulturist UMaine Extension Penobscot County

  • Make native plant species an integral part of your garden design. Viburnum species, for example, have a high ecological value because their early flowers serve as a food source for pollinators, their foliage hosts butterflies and moths, and their fall fruit are treasured by birds.
  • Continue planting food crops. Don’t fret if your garden isn’t completely planted by the first of June. Follow the suggested planting dates listed in the last column in this chart.
  • Apply mulch to minimize weed pressure and conserve moisture. Start with a layer of newspaper, cardboard or all those paper grocery bags you’re suddenly accumulating, then cover with an organic material such as bark, wood chips, pine needles or straw.
  • row covers and tomato supports
    Protect crops with row covers and install supports before plants get too big. Photo by Art Shaw.

    Protect crops from insect pests. Immediately cover all brassicas and cucurbits to protect from flea beetles and cucumber beetles (respectively). Once both male and female flowers are present on cucurbits, remove row cover to allow pollinators to work their magic. Most brassicas can be left under a lightweight row cover all season long for insect protection. Be sure to lift the row cover occasionally to pull weeds.

  • Install supports before plants get too big. Peas, tomatoes, and beans will quickly get hard to wrangle if left unsupported for too long. Learn more about staking, trellising, basket weaving, and caging tomatoes. Many cut flowers benefit from being supported as well.
  • Prepare for Japanese beetles. These well-known insects usually show up in Maine between the last week of June and the first week of July. Remove beetles daily (best in the morning) by knocking them into a bucket of slightly soapy water. Bagged pheromone traps, if poorly placed or left unmanaged, can potentially increase beetle populations by attracting beetles to your yard.
  • container garden
    The possibilities are endless with container gardens.

    Establish a container garden. Countless vegetables and herbs grow very well in containers. The aesthetic possibilities are endless when adding flowers and ornamental foliage plants.

  • Label your plants with the variety and date planted. Labels will help you avoid mixing up your hot peppers with your sweet peppers or letting  your pickling cucumbers grow too large thinking they’re a slicing cuke.
  • Gather food preservation supplies and start researching the best method to preserve the bounty you’ll gather from your garden and the farmers’ market.
  • Start a compost pile. Not only is compost good for building soil structure, it reduces the amount of materials directed into the waste stream.
  • Connect with a UMaine Extension gardening expert in real time five days a week during our virtual office hours (M-F, 11-1).
  • Record and appreciate the work you’ve done. Spring and summer come and go so quickly, that it can be challenging to remember all you’ve accomplished, as well as the challenges you’ve overcome. Gardens begin to thrive in June, and there can be lots of intense work leading up to that point. Starting a garden journal can help you keep track of what’s new, what’s been moved/removed, or adjusted, and can provide easily-forgotten details to guide your decisions in subsequent seasons. And, most important of all, make time to sit or take a contemplative walk around your yard and gardens. You’ve put time, effort, and energy into your creation, so now enjoy!

Gardener Profile: Herb Crosby

By Lisa Colburn, the author of The Maine Garden Journal and writer of the Regional Gardening Guides with a focus on Zone 3 and 4 gardens for the Burpee Seed Company.

Master Gardener Herb Crosby, retired professor of Engineering Technology at the University of Maine, has equal enthusiasm for things botanical and mechanical.

Herb and Judy Crosby
Herb and Judy Crosby. Photo by Lisa Colburn.

Herb and his wife Judy have a lovely home that sits at the top of a slope in Orono. A river of daffodils meanders its way down both sides of the property and then up and down the street. Magnolias have been in bloom for weeks and as one variety fades, another will take its place. Tall, dark pines and spruce at the back of the property create the perfect contrasting backdrop for the emerging cloud of blooms.

Herb was fortunate to grow up in a family that gardened extensively. His parents, Ruth and Howard Crosby, donated their 90+ acre family property to the town of Hermon in 1995. The acreage is home to over 60 gardens containing 280 varieties of trees, over 1500 varieties of perennials, and an abundance of animals, birds, and insects. This ecological sanctuary is now called Ecotat, a non-profit, public garden.

It’s no surprise then that Herb has a keen interest in gardening. He became particularly interested in magnolias in the early 1980s after his parents introduced him to Roger Luce, a Newburg native known as the “King of Magnolias.” Luce became a mentor and cherished friend. Whenever Herb visited Roger, he walked away with plants, including magnolias! Roger Luce has since passed away, but Herb’s garden is peppered with memories from his dear friend, and Luce’s antique tractor, restored by Herb, now chugs along in Orono.

Herb and Judy have hundreds (and hundreds) of magnolias on their property. Behind their home is a nursery of magnolias, many started from seeds they’ve crossed themselves. Almost every visitor leaves with a magnolia seedling in hand. Herb is a long-time member of the Magnolia Society International, an organization that made it possible for him to exchange magnolia seeds with world-renowned experts from around the globe.

Magnolias contrast
Magnolia contrast well with the dark foliage of conifers. Photo by Lisa Colburn.

As magnolia blossoms fade, apple trees (another botanical passion for Herb) burst into bloom. Hanging labels document the names and dates of grafts from heirloom varieties. Over the years, Herb and Judy have grafted hundreds of branches. In fact, most of their apple trees have grafts from other varieties. Herb keeps track of each graft in an Excel spreadsheet. Though not all are successful, grafting has become an enjoyable annual ritual.

One of the things you’ll notice in the Crosby gardens are the fence barriers around many trees, shrubs, and their vegetable garden. The area has a high deer population, and despite using spray repellents, the Crosbys must also enclose valuable plants to protect them from hungry foragers.

Herb is an avid photographer who regularly posts marvelous photos to his Google Photo account to share with family and friends. His photo documentation has been a fabulous way to watch how his yard has evolved over time. Click this link to view Herb’s 2019 garden photos, which he so generously made available. He also has a YouTube channel where he posts videos of his garden and the gardens he visits, often accompanied by music.

But, don’t think he’s just concerned with the fine, delicate world of nurturing plants and taking pretty pictures. Herb’s other pursuits appear to be a polar opposite! His channel also features his fascination with machinery, particularly antique mechanisms: steam engines, old tractors, timeworn dump trucks, vintage cars, historic log haulers, old sawmills, and more. In fact, Herb is the President of the Maine Forest and Logging Museum.

Garden art
Rustic garden art are gifts from daughters. Photo by Lisa Colburn.

Perhaps the connection between the two areas of interest is Herb’s enthusiasm for learning how things work and understanding the details. Not content with simply having a few magnolias, he is motivated to understand everything about them. Herb was already an experienced gardener when he retired. But he decided to complete the Master Gardener training in Penobscot County because, like many gardeners, he knew that one can never get enough information about gardening. The added bonus: the pleasure of spending time with others who share his excitement about anything related to gardening!

Herb and Judy have inspired their two daughters to become avid gardeners and their two granddaughters are likely to receive the “gift.” Herb’s enthusiasm is infectious!

Editor’s note: Just a day or two after reviewing this article, I was delighted to stumble across this fun Washington Post article about Herb’s lovely neighborhood. It’s not about gardening, but it sure cultivates community spirit!


What Is It?

Cecropia Moth
Photo by James Dill.

Answer: Cecropia Moth

The Cecropia Moth (Hyalophora cecropia) is a type of moth referred to as a giant silk moth (family Saturniidae). It is North America’s largest native moth, with wingspans of over 6.2 inches having been documented! Read more.

Bees of Maine: Family Halictidae

By Jennifer Lund, Maine State Apiarist, Department of Agriculture, Conservation and Forestry, Division of Animal and Plant Health,

Nearly 4,000 bee species have been identified in the United States. Maine has  more than 270, representing six families. This is the third of a series of articles where we explore the types of bees found in Maine and learn about their biology, foraging preferences, and nesting requirements.

Family Halictidae (Halictids, Cuckoo, and Sweat Bees)

Some members of this family are metallic blue or green, but most are black or brown. They are small (0.1 – 0.6 inches in length), slender, and range from bald to moderately hairy. Most species are solitary, but some are sub-social where multiple females build and defend a single nest. Females are generalist foragers and carry pollen on the hind legs or thorax. There are eight genera found in Maine with Lasioglossum being the most diverse.

Lasioglossum spp. (sweat bees) is a very diverse genera, containing well over 1000 species worldwide. In Maine we have 52 species. They  are commonly called “sweat bees” because they are attracted to animal sweat, which they drink for salt and micronutrients. Sweat bees are small, slender, and often black, metallic green or metallic blue. They are generalist feeders and carry pollen on the upper portion of back legs. Lasioglossum species exhibit a wide range of social behaviors, including solitary, communal, and social habits. In social colonies, daughters care for the young. In communal colonies, several reproductive females will lay eggs in and defend a single nest opening. Most species nest in sandy soil on flat ground and line brood chambers with a wax-like secretion to protect developing larva. A few species nest in soft wood.

Sphecodes spp. (cuckoo bees) are small to moderate in size, slender and relatively hairless. They have shiny brown to black head/thorax and red abdomens. Sphecodes spp. are cleptoparasites, meaning they lay their eggs in the cells of another species. Sphecodes spp. primarily lay their eggs in the cells of other Halictid species. After hatching, the Sphecodes larva consumes the resources in the cell (nectar and pollen) and often any other bee larva/egg in the cell. Adult Sphecodes spp. lack scopa, or pollen-collecting hairs, since they only visit flowers to drink nectar, not to collect pollen which is needed to feed developing larva. There are 14 species in Maine.


Possibly Family Halictidae. Photos by Megan Leach.

Ask the Expert!

You’ve asked us some great questions over the years! Here are a few examples from this month in a prior year. To read more inquiries from fellow Maine gardeners and answers from Extension experts, check out our Ask the Experts website.

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

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

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

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

While larvae feeding on roots can cause damage, there is no remedy at this point. The best approach is to manage adult populations, which will lead to a reduction of egg-laying.

Q: When should I dig up and replant my Irises?

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

Irises need dividing every  3 to 5 years, when they become crowded. Decreased bloom and rhizomes pushing out of the soil are signs that they are ready for division.

Divide irises in the late summer or early fall, after plants have bloomed. Cut leaves to one-third their full height. Dig under a clump of rhizomes and lift out the whole clump at once. Wash away soil with a steady stream of water.

Cut rhizomes apart with a sharp knife, removing any tissue that is not firm and healthy. Diseased tissue should be destroyed rather than added to the compost bin.

Each division must have at least one growing point (or fan of leaves), a few inches of healthy rhizome, and a number of well developed roots. Plant divisions about 12” apart in a sunny spot, with the rhizome just under the soil. Irises planted too deeply or in soil with too much nitrogen will not flower well.

Siberian irises have a different growth habit, with smaller rhizomes that grow together in a tight mass. They can go 4-6 years before division, which may be done in either early spring or late summer. To divide an established clump is quite a challenge. You will need a strong back and a strong long-handled shovel to lift the clump, and a pruning saw or axe to cut it into pieces. Divisions of 2-4 fans should be planted two feet apart, with the rhizomes an inch or two beneath the surface, and watered in well.

Siberian iris
Siberian iris. Photo by C. Eves-Thomas.

Doug Tallamy Invites Gardeners to Help Create a Homegrown National Park

Reviewer: Naomi Jacobs, Master Gardener Volunteer

Tallamy, Doug. Nature’s Best Hope: A New Approach to Conservation that Starts in Your Yard.

Timber Press, 2020. 256 pages. Available in Kindle, Audio, and Print with prices ranging from $12.99 to $18.99.

Book Cover
Nature’s Best Hope by Douglas W. Tallamy. Cover art used with permission.

Entomologist Doug Tallamy’s 2008 book, Bringing Nature Home, enlightened many gardeners to the importance of using native plants in home landscapes. Tallamy and his graduate students at the University of Delaware counted the varieties of caterpillars found on hundreds of different North American plants. They found a remarkable difference between the ecological value of native plants and the relative sterility of many non-native species that had been planted for beauty alone. A native white oak, for instance, will support over 500 different caterpillars, as well as the birds who feed on the caterpillars, and the butterflies and moths that the caterpillars will become. On the other hand, the non-native lilac will support 40, and ginkgo only 5. Perhaps 75% of insects are host-specific; they will feed or take pollen from only certain plants and need very precise conditions to successfully reproduce. Because they have evolved in a particular place alongside certain plants, they may not be able to make use of plants that come from elsewhere. And of course, insect pollinators are crucial to human food production, and caterpillars are a primary source of food for birds. The health of insect populations is essential for life on this planet.

Nature’s Best Hope updates Tallamy’s earlier work with the latest research and a plan to enlist home gardeners in an effort to “re-nature” our landscapes. Some 40 million acres in the United States are devoted to home gardens. But the standard landscape is an ecological desert that contributes almost nothing to ecosystem diversity and resilience: a few specimen trees in a large lawn, with foundation plantings of non-native ornamental shrubs and perennials. If half of this area could be given over to native plants, a 20-million-acre “Homegrown National Park” would be created, providing habitat and migration corridors for insects, birds, and other wildlife.

To achieve this goal requires a new approach to conservation. Though many public parks and preserves have been created, along with conservation easements on private land, these will never be enough to slow the dramatic loss of species currently under way. Tallamy makes a persuasive case that we must practice conservation in our own backyards. If we do so, we will be richly rewarded with a more vital environment and a transformed relationship to nature. We don’t have to give up our favorite non-native ornamentals, or even all of our lawn, but simply to shift our aesthetic and our emphasis to see the beauty and the value in the ecological services provided by the native landscape and its inhabitants.

Tallamy is a master at communicating complex scientific concepts in accessible language, using concrete examples. His writing is personal and often amusing as well as informative, a pleasure to read. The book is full of practical information on how to create an ecologically successful landscape. A helpful section of Frequently Asked Questions gives voice to skeptics and answers concerns such as whether the native landscape will increase tick populations or increase fire risk.

Nature’s Best Hope recaps some ideas that will be familiar to readers of Tallamy’s earlier books. An increased tone of urgency reflects the unabated pace of species decline over the past decade, and much of the information presented here is disheartening. However, as the title suggests, the book is predominantly hopeful. It presents a new and inspiring vision of what could be achieved if concerned individuals join together to transform the common attitudes and practices that have shaped our own backyards. As Tallamy writes, “The good news is that we can fix our ecological problems by indulging rather than by sacrificing.” By healing “our damaged landscapes right now . . . we will be enriching our lives” (12).

What Each of Us Can Do: A list from Doug Tallamy

1) Shrink the lawn. Think of it as an “area rug, not wall to wall carpeting” (206).

2) Remove invasive plants that crowd out native plants and reduce ecological diversity.

3) Plant keystone genera, those few plants that support the greatest number of insect species. In Maine, the most productive trees are oaks, cherries, birches, and willows. Top rated perennials are goldenrods, asters, and sunflowers.

4) Be generous with your plantings. Build layers of shade trees, understory trees, shrubs, grass, and perennials to maximize pollen and nectar sources.

5) Plant for specialist pollinators. Some bees, for instance, lay eggs only in pithy stems that are easily excavated, such as asters or elderberries. If you cut these stems back just part way in the fall, the bees can complete their reproductive cycle.

6) Network with neighbors to increase your impact. Reach out to coordinate efforts toward a common goal, such as building monarch habitat on a larger scale than any one person could do alone.

7) Build a conservation hardscape. Install window well covers to avoid trapping small animals, set your mower to four inches, add a bubbler, use multiple small bee hotels (because a large one makes it easier for predators to find the bees), and use a motion sensor on your security light to protect moths.

8) Create pupation sites under trees, using ground covers, leaf litter, rocks or decaying logs.

9) Don’t spray or fertilize. A landscape of native plants needs no fertilizer, and invasive plants respond vigorously to a high nitrogen environment. To avoid harming beneficial insects, use non-chemical means of controlling mosquitoes or other pests.

10) Educate your neighborhood civic association about the value of native plantings. Work to change zoning codes or HOA agreements that ban natural landscapes.

(Bolded phrases quoted from Tallamy, Chapter Eleven, “What Each of Us Can Do,” pp. 205-211)

Did You Know?

You can connect with your local UMaine Cooperative Extension horticulture staff in real time M-F, 11am-1pm through June. Visit our website for the link to our Zoom virtual office or call +1 312 626 6799 (meeting ID 965 8976 1572). It’s free and open to the public. No registration required. Drop-ins are welcome!

CarrotsVictory Garden for ME is a new series of short pre-recorded videos geared towards Mainers growing their first vegetable garden.

Growing Vegetables and Herbs in Part Sun

By Kate Garland, Horticulturist, UMaine Extension Penobscot County

Many gardeners are faced with landscape conditions that limit the types of plants they’re able to grow. For those who aim to grow food, insufficient sunlight can be a big challenge. While you might not be able to grow everything you’d traditionally produce in a full-sun site, there’s still hope for a vegetable garden with 4-6 hours of direct sunlight daily.

Assessing light conditions

When determining light exposure in sites surrounded by deciduous trees, keep in mind that lighting may vary dramatically when trees leaf out and as the sun angle changes throughout the year. South facing sites typically have the greatest sun exposure. The timing of exposure is also a factor. Midday and early afternoon sun is more intense than morning sun. In other words, an hour of sun at 7:00 a.m. has less photosynthetic value than an hour of sun at noon.

Tip: When looking for a sunny spot for a straw bale garden, our family placed rocks around the yard in the morning on a sunny day and committed to checking the light every two hours. With chalk, we’d mark the time on the rock when it was sunny, or turn the rock over and put a frown on it if it happened to be in the shade before 8 hours had passed.

Choosing the right crops

Lettuce MixLeafy crops like lettuce, spinach, Swiss chard, kale, beet greens, arugula, and parsley all perform well in part sun. Fruiting crops, such as tomatoes, peppers, squash, cucumber, zucchini, and eggplant all need at least 8 hours of direct sunlight for good production.

Using space wisely

  • Practice succession planting to keep the space productive for the entire growing season. When an initial crop of leafy greens begins to be less productive, remove it and sow another crop that will develop in the time frame you have left in the season.
  • Harvest crops over a longer period. Instead of harvesting whole heads of leafy greens, simply remove some outer leaves and harvest again a week or two later when the plants have pushed more growth.
  • Keep taller crops to the north side of shorter crops to minimize additional shading.

Avoid the temptation to try sun-loving crops in shadier sites. They might survive, but likely won’t thrive. Plant what will work in your site and purchase delicious fresh tomatoes at your local farmers’ market instead.

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University of Maine Cooperative Extension’s Maine Home Garden News is designed to equip home gardeners with practical, timely information.

For more information or questions, contact Kate Garland at or 1.800.287.1485 (in Maine).

Visit our Archives to see past issues.

Maine Home Garden News was created in response to a continued increase in requests for information on gardening and includes timely and seasonal tips, as well as research-based articles on all aspects of gardening. Articles are written by UMaine Extension specialists, educators, and horticulture professionals, as well as Master Gardener Volunteers from around Maine, with Katherine Garland, UMaine Extension Horticulturalist in Penobscot County, serving as editor. Special thanks to our 2020 Master Gardener Volunteer co-editors Naomi Jacobs and Abby Zelz.

Information in this publication is provided purely for educational purposes. No responsibility is assumed for any problems associated with the use of products or services mentioned. No endorsement of products or companies is intended, nor is criticism of unnamed products or companies implied.

© 2020

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