Perennials Designed to Withstand the Harshest of Winters
Need a hardy creeper? Or, how about a colorful tall plant for back of the border? Look no further than the sedum family. These rough-and-tumble plants survive both hot summers and cold winters. Sedums are also drought tolerant, so they're ideal if you live where rainfall is scarce -- or if you just hate watering. One of the toughest members of the family is 'Dragon's Blood'. This hardy groundcover is smothered in rich green leaves with red edges. It has deep red blooms in late summer and when fall rolls around the entire plant turns red. Many varieties are hardy to Zone 4.
Survival Tip: Leave the faded flower stalks of sedums in place over the winter. They provide winter interest poking through the snow as well as nutritious seeds for visiting birds.
For decades, northern gardeners have relied on peonies to provide a spring festival of color and fragrance. Besides being drop-dead gorgeous, peonies are also tough enough to sleep soundly through the coldest winters. They pop back up at the first signs of warm spring weather. Peonies come in a wide variety of flower forms and colors. Most are hardy in Zone 3.
Survival Tip: Trim dead peony foliage back before winter. That way, the new spring foliage won’t have to poke through the previous year’s dead leaves.
Coneflower, often called by its scientific name, Echinacea, is an American native that naturally withstands harsh winters. The plants develop beautiful, daisylike heads of purple blooms through the summer and fall. Newer varieties offer a wide variety of colors, such as yellow, orange, and white, and flower forms. However, some of the modern hybrids are not as winter hardy as the native form, so read the plant label before you buy to check for cold tolerance. Most varieties are hardy to Zone 3 or 4.
Survival Tip: Help coneflowers and other newly planted perennials survive their first winters by clipping back their dead stems and covering them with a 1–2 inch layer of mulch after they go dormant in the fall. Uncover them in the early spring after the soil thaws.
It’s no secret that the populations of honeybees and other important pollinators are starting to decline. But you can help by offering them a nectar-rich meal when they visit your garden. Monarda, also called bee balm, is a great example. This must-have perennial develops beautiful flowers that are attractive to both gardeners and insects. Monarda grows 2-3 feet tall and comes in a pink, red, orange, purple, and white. In ideal conditions, some varieties can become invasive, so plant Monarda where it can’t spread. Monarda is hardy to Zone 4.
Survival Tip: Perennials are better able to tolerate winter conditions when they are in peak form. Apply a slow-release granular fertilizer in early spring to keep plants well fed through the growing season. And always mulch to prevent weed competition and maintain consistent soil moisture.
Much hardier than its modern cousins, wild columbine (Aquilegia canadensis), is a delightful spring bloomer that will eventually form large colonies in partially shady locations. The nodding, pink and yellow flowers are produced on wiry stems that seem to dance on every spring breeze. Wild columbine prefers a rich, moist soil, growing 2-3 feet tall. Each plant might only live a few years, but the plants spread easily so it’s hard to tell new plants from old. Many varieties are hardy to Zone 4.
Survival Tip: Instead of bagging your fall leaves, spread them lightly over your perennial beds to help protect them from the freeze/thaw cycle over the winter. For best results, shred the leaves before applying to prevent them from forming an impenetrable mat that your plants can’t penetrate in the spring.
Plants That Give You the Most Bang for Your Buck
Learn which plants give you the biggest return on your investment.
Electrify your shade garden with the brilliant colors of Heuchera, commonly called coralbells. These beauties will pack a ton of color into even the shadiest garden bed. Prized for their colorful foliage, Heucheras are available in purple, green, yellow, orange, and red. As a bonus, the plants send up spikes of pink or white bell-shape flowers in the early summer. Heuchera also makes a great container plant paired with other perennials or shade-loving annuals, such as wax begonia, Torenia, coleus, Hypoestes, and impatiens. Many Heuchera survive Zone 4 winters.
Survival Tip: If you live in a cold climate, most perennials won’t survive the winter if they are left in containers. Save the plants by popping them into the ground at least a month before the first expected frost in your area.
Native to northern Turkey and Russia, Siberian iris isn’t bothered when the thermometer drops below zero. These super-reliable perennials put on a spectacular spring show of fleur-de-lis shape blue, purple, lilac, yellow, or white flowers. The plants grow 3-4 feet tall and produce thick clumps of dark green, straplike leaves. Siberian iris prefers a rich, slightly moist soil, yet it will still look good even during drought. It’s also more resistant to iris borer than it’s slightly showier cousin, bearded iris. Siberian iris easily withstands Zone 3 winters.
Survival Tip: Voles, rabbits, and mice will occasionally dine on dormant perennials during the winter. Pull back protective mulches every few weeks to check for rodent damage.
Throughout the summer, ‘Moonbeam’ coreopsis produces a seemingly endless supply of cheerful yellow flowers. It’s a rugged variety that takes cold winter temperatures in stride. However, not all coreopsis varieties are as winter hardy as ‘Moonbeam’, so read the plant label before you buy. To keep ‘Moonbeam’ in top form, dig and divide the plants every several years.
Survival Tip: To ensure winter survival, select perennials listed for at least one zone further north. For example, if you garden in Zone 4, choose those recommended for Zone 3.
Once established, Baptisia can live for decades. This hardy, prairie native has pretty gray-green foliage topped with sprays of blue, purple, white, or yellow flowers in the spring. Because of its prairie heritage, Baptisia can tolerate both summer heat and below-zero winters. Also known as false indigo, Baptisia is so hardy it can often be found thriving around long-abandoned farmsteads and ranches. Baptisia grows slowly, so buy the largest plants you can find to get a faster flower show. Baptisia is hardy to Zone 3.
Survival Tip: Baptisia can be a bit fussy when transplanted, so place it in your garden in the early spring. That way the plant will have plenty of time to develop a strong root system before fall.
If winter weather continues to kill your lavender plants, switch to catmint. These extra-hardy perennials develop wave after wave of lavenderlike blooms through the spring and summer, making them an ideal substitute for less winter hardy lookalikes, such as lavender. And, like lavender, catmint also has fragrant leaves that are a delight to rub between your fingers. There are a number of excellent catmint varieties to choose from, but in our Test Garden®, ‘Walker’s Low’ is a staff favorite. Growing about two feet tall, ‘Walker’s Low’ makes a great border plant that is unfazed by climate extremes. Shear back the plants after the flowers fade and you’ll get a second wave of bloom in late summer. Catmint survives as cold as Zone 3.
Survival Tip: Nepeta starts to bloom almost as soon as it breaks dormancy in the spring, so clip the plants back in the fall. This will also allow snow to accumulate over the crown of the plants, which helps insulate them in the winter.
At first glance you might not think the delicate looking blooms of lily-of-the valley are tough enough to handle the extremes of winter. But, nothing could be further from the truth. In fact, these fragrant beauties have a tough-as-nails constitution that shrugs off bone-chilling temperatures. Plus, lily-of-the-valley is shade tolerant, making it a great groundcover for wooded backyards. Most commonly seen with white flowers, there are also varieties with pretty pink blooms. There’s also a variegated form with dark green leaves with white stripes. This plant is hardy to Zone 3.
Survival Tip: During the winter deer can do a lot of damage to perennial gardens. To avoid destruction, select deer-resistant plants, such as lily-of-the-valley.
If you love to make dried floral arrangements, wreaths, or crafts projects, be sure to include some Artemisia in your garden plan. This almost indestructible perennial is prized for its silvery gray, aromatic foliage that retains its color even after drying. Common names for this plant include: wormwood, mugwort, and southernwood. Varieties differ in shape and form, but Artemisia lactiflora grows 5 feet tall and develops loose sprays of small white flowers in the summer. It’s a super-easy sun-lover that tolerates heat, drought, and deep cold. Artemisia also has few insect or disease problems. Plant it in the back of your border as a color foil for brighter flowers up front. Hardiness ranges from Zone 4 to Zone 5, depending on variety.
Survival Tip: Cold, wet soil can cause problems for perennials like Artemisia that have Mediterranean roots. Plant them in a sandy spot where snow and ice will drain quickly during thaws.
An American native, Heliopsis, often called ox-eye daisy or false sunflower, produces masses of cheerful yellow flowers all summer long. Heliopsis is a large perennial that easily grows 3-6 feet tall and 2-4 feet wide, so plant it where it won’t get squeezed by its neighbors. It isn’t fussy about soil type but does need full sun to keep stems upright. If grown in partial shade, Heliopsis will flop over. The blooms make great cut flowers and the more you cut, the more the plant will produce. Heliopsis is hardy to Zone 3.
Survival Tip: Cold weather isn’t the only thing that kills perennials during the winter. Sometimes plants die because they have shorter lifespans than other species. Heliopsis, for example, might die back naturally every few years. Just start new plants if the old ones disappear.
Keep your garden colorful through the fall by adding a generous dose of New England asters. These easy-care natives burst into bloom just as other perennials in your garden start to look pale and peaked. Growing 3-6 feet tall, New England asters also are an important nectar plant for migrating Monarch butterflies that feed on the flowers as they head to Mexico. Available in shades of pink and purple, New England asters look terrific paired with ornamental grasses and chrysanthemums. Many asters tolerate Zone 4 winters.
Survival Tip: After the plants finish blooming, cut the tall stems back to the ground to prevent them from flopping over under the weight of the snow. This will keep the plant tidier and healthier in the spring.
Make hostas the backbone of your shade garden. Unfazed by cold winters, hostas just keep growing bigger and better every year. Because these hardy perennials are available in a seemingly endless selection of shapes, sizes, and colors, they’re a lot of fun to mix and match in your garden. They also make great companions for other shade-lovers such as astilbe, Lamium, Epimedium,Heuchera, and bleeding heart. Hostas also are attractive to hummingbirds that dine on the nectar-filled flowers. Hostas can survive Zone 3 winters.
Survival Tip: When you plant hostas or other perennials, make sure to place them in the hole at the same depth they were growing previously. If the top of the roots, or crown, is exposed to freezing weather, the plant might die.