With its extreme weather and short summers, Maine can seem daunting to novice gardeners, as well as green thumbs relocating from warmer climates. The good news is gardening in Maine really isn’t more difficult than anywhere else. In fact, Boothbay landscape architect Bruce Riddell says flower gardeners in many parts of the state can choose from a bigger palette than their Southern counterparts, who are limited to species that can tolerate months of extreme heat and drought. “We’re blessed in Maine with long, warm summer days and cool nights,” he says, “and lots of perennials are very hardy here.”
Helping them thrive is a matter of knowing the obstacles and developing strategies for dealing with them. “Our growing season is limited — that’s the biggest challenge,” says Marjorie Peronto, a University of Maine Cooperative Extension educator in Hancock County and the co-author, with Reeser Manley, of The New England Gardener’s Year and The Life in Your Garden. “So you enjoy it while you can, and if you plan appropriately, you can have a great garden.”
Know Your Zone
Maine is divided into six USDA plant hardiness zones — regions defined by their average annual minimum temperature. (Find yours here.) Knowing your zone helps you choose perennials, shrubs, and trees that flourish in your climate. If you live in Kittery, for example, you’ll want plants that are labeled hardy to zone 6a, meaning they can withstand temperatures as low as -10 degrees. Presque Isle, by contrast, is zone 4a, where it’s not uncommon to see midwinter temperatures as low as -25 to -30 degrees.
“I err on the conservative side,” says Peronto, who lives in Ellsworth. “We’re zone 5b, but I recommend people get plants that are hardy to zone 4, which will probably consistently make it through our winters.”
Still, it can be fun to push the envelope, particularly since every property has microclimates, where conditions may be gentler or harsher than average. Why not try your luck with some beautiful mild-climate-loving buddleias in a spot sheltered from wind? “At worst, they end up being expensive annuals,” Riddell says. His advice: “Make sure the base of your garden is filled with the toughest, hardiest plants, and then go ahead and sprinkle in your mad-scientist perennials. Just know that you might lose them.”
Prepare Your Site
Before you start digging a bed, track the sun in your yard over the course of a day, advises Tom Estabrook, owner of Estabrook’s garden center in Yarmouth. “Measure the number of hours of sunlight. Is it morning or afternoon sun? Is there direct sunlight, shade, or part shade? It makes a difference in helping you determine what you can grow where.”
Take extra care when selecting plants for sites exposed to winter’s cold winds. Azaleas, mountain laurels, rhododendrons, and other evergreens are susceptible to winter burn, which turns the leaves brown and may kill the plants. Ledge can also be a problem, particularly along the coast where it may lurk just a few inches under the soil, leading to poor drainage that wipes out plants. Deal with it by building raised beds or a retaining wall to hold supplemental soil.
Maine soils tend to be acidic, which is preferred by plants like heathers, hydrangeas, and rhododendrons, but most do better in a more neutral environment. An $18 Cooperative Extension soil test can tell you your soil’s pH — and a whole lot more. “I think a soil test is like a blood test,” Peronto says. “If you don’t do one, you don’t know what you’re working with.” The process is easy: fill the kit’s small box with soil, answer a few questions, and send it to the lab. In a few weeks, you’ll receive a report listing your soil’s pH, levels of organic matter and nutrients, as well as specific recommendations for amendments, such as lime for reducing acidity or blood meal to raise nitrogen.
Mix It Up
The most reliable plants are native Maine species and “nativars” (cultivars derived from natives) — perennials like asters, bugbanes, buttonbushes, goldenrods, hay-scented ferns, pagoda dogwoods, red maples, and summersweets. “They’ve proven themselves over a long period of time,” says Jennifer Dunlap, a staff horticulturalist at Coastal Maine Botanical Gardens in Boothbay. “They’re accustomed to the climate and habitat, so they need less maintenance. Plus, they’re beautiful.”
Countless showy nonnative species do well here too, and as long as you’re paying attention to hardiness, there’s no reason not to use them. Hard-to-kill choices include astilbes, black-eyed Susans, coneflowers, catmint, daylilies, delphiniums, hollyhocks, hostas, sedums, and salvias. For shrubs and trees, consider boxwoods, hydrangeas, kousa dogwoods, lilacs, star magnolias, spireas, and yews.
Tough as these plants are, they still need to be babied while they’re getting established. “You can’t just stuff them in the ground and go on vacation,” Peronto says. “Any tree or shrub — and I’d say any perennial too — needs 1 to 2 inches of water per week over the root zone during the first year. That’s so they can extend that root system down into the soil and anchor themselves well.”
Avoid creating a monoculture by, say, planting only ash trees on your property. All it takes is one pest — like the emerald ash borer, a destructive beetle that infests ash trees — to wipe out your landscape, much the way Dutch elm disease killed millions of American elms and denuded city streets and parks in the 1930s. Plant diseases and insect pests tend to be selective — what attacks an ash won’t attack a maple — so variety is your best protection against such devastation.
Don’t Be So Serious!
Gardening with wildlife is a fact of life in Maine, and it comes with its own set of problems. Deer, in particular, can be destructive, gobbling up balsams, daylilies, Fraser firs, hostas, tulips, and more. You can get a dog, erect a fence — it’s got to be at least 8 feet high — or select deer-resistant plants. Even then, they may surprise you, ignoring Fido, finding a way around the fence, or nibbling plants they’re supposed to dislike.
A laidback attitude helps. “We have a fence around our vegetable garden, we have a dog, and we still have deer,” Peronto says. “I don’t really mind. They’re beautiful, and they’re not devastating my plants. My philosophy is, try to live with the creatures around us.”
That relaxed approach pretty much sums up the secret to successful gardening in Maine, or anywhere. “Gardening is learning about horticulture and botany and plants and what lives and what doesn’t,” Riddell says. “Experiment and have fun.”
Most Likely to Succeed
These hardy Maine natives can turn even the blackest thumb green.
Northern Bayberry (Myrica pensylvanica): With glossy, dark-green foliage and clusters of fragrant, waxy grayish-white berries, bayberries makes great anchor shrubs throughout the garden.
Bearberry (Arctostaphylos uva-ursi): This evergreen groundcover has pinkish-white flowers that give way to red berries. It’s super tough and can withstand full sun and dry periods.
Pagoda Dogwood (Cornus alternifolia): This small tree bears white blooms in spring and bluish-black fruit in summer. Foliage turns red, yellow, and orange in fall.
Summersweet (Clethra alnifolia): Summersweet provides habitat and food for birds and insects, and it thrives in full sun, dappled shade, and even swampy spots.
Swamp Milkweed (Asclepias incarnate): Monarchs and other butterflies love this perennial, with its showy dusty-rose blossoms.
Find a full list of Maine native plants and shrubs, as well as invasive species to avoid, here.
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