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Colorful Survivors
Which power perennials can withstand a harsh winter?

Photography courtesy of David J. Frank Landscape Contracting Inc.

September 2016

As you prepare for winter’s icy presence, consider what snow, sleet and freezing rains might do to your plantings. Yet don’t panic. There is hope.

After studying the many microclimates and soil conditions of the Milwaukee metropolitan area, Stephanie Wilson, a landscape architect with David J. Frank Landscape Contracting Inc., has the inside scoop on protecting flowers and encouraging proper plantings. Lake Michigan and geology play a large role in guiding flower selections that are appropriate around here, she explains.

Wilson emphasizes that native flowers and grasses are great choices for area gardens because they are reliably hardy and often provide habitat and food for Wisconsin’s insects and animals. They generally need less special protection and care once established because they have adapted to the area’s climate, soil and water conditions. Many of the native wildflowers can be left in place for fall and winter and will attract birds and other native animals. The seed heads and arching foliage also create visual interest in the winter landscape, Wilson adds.

But first, make sure your garden is properly prepared to deal with winter’s rigors. Autumn is a good time to assess if mulch needs to be added to the planting beds — Wilson says 3 inches is ideal. When kept close to that depth, mulch suppresses weeds, adds organic matter, moderates soil temperature and retains moisture.

Peonies should be cut back to the ground and foliage removed to deter fungal diseases that can overwinter in the soil. Fall is also a great time to split peonies, but be aware that doing so may affect flowering the following year. Add bulbs to perennial beds for more spring color. Hardy crocuses and daffodils are other great choices for an early palette when waiting for other shrubs and perennials to leaf out. Wilson likes to add alliums for variety.

Most perennials and shrubs located in the Greater Milwaukee area’s growing zones do not need winter protection unless they are in an exposed, windy location or in an area that makes them susceptible to salt damage. But for gardeners hoping for honeybees in the spring, vegetation such as aromatic monarda is a great option. The hardy floral should be planted in conjunction with tough perennials (think New England aster, joe-pye weed and goldenrod) to extend the length of time nectar is available to the pollinators. Choosing nonhybridized plants is important because the hybridized varieties often provide less nectar and pollen, according to Wilson.

For surviving the roughest Wisconsin winters and providing year-round interest to the landscape, Wilson suggests the following perennials:

» Big bluestem — a bunchgrass with blue-green stems that can grow 4 to 8 feet tall.

» Prairie dropseed — a showy plant that looks like a fountain of green, making for distinctive borders.

» False sunflower — a plant with daisy-like flowers and a lengthy summer bloom, it can grow 3 to 4 feet tall.

» White gayfeather — the creamy-hued flowers of this plant perk up in early summer.

» Foamflower — a perennial that spreads rapidly in clumps and grows in partial to full shade.

Siberian iris, as well as other irises like the native blue flag iris, provides reliable color in the landscape year after year. Frost-resistant hellebores, offering more than 20 varieties, ensure early spring flowers and interesting foliage throughout the summer. Rugged wild onion and silky prairie smoke are also winter survivors. Baptisia, aromatic catmint and lilies of the valley last for decades when properly cared for.

One of the great things about Wisconsin gardens is being able to enjoy them through all seasons, enthuses Wilson. Fall preparations are fun because of the chill in the air and anticipation, either good or bad, of the change from autumn to winter. This seemingly short transition from a pleasant fall day to freezing temperatures presents a challenge at the end of the growing season. So be sure to complete the necessary cleanup to ensure your multi-hued garden emerges healthy when spring actually does arrive. m


This story ran in the September  2016 issue of: