When you’re coping with harsh winter weather that lashes your face, makes driving treacherous and batters your house, should you also worry about your trees, shrubs and other garden plants?
Probably not, said Julie Janoski, manager of the Plant Clinic at The Morton Arboretum in Lisle. Most hardy plants are safely dormant at this time of year. “If you’ve chosen your plants well, they can probably handle a Chicago winter,” she said.
Here are some tips from the Plant Clinic for handling winter in the garden.
Snow is good for plants. It provides excellent insulation because it contains far more air than ice. “A layer of snow will protect the roots of trees and shrubs and the crowns of perennials against bitter air temperatures,” Janoski said. When the snow eventually melts in spring, it will provide moisture.
Branches can take the weight of snow. Trees and shrubs bent down by a heavy snow load can be an alarming sight. But most of the time they bounce back when the snow melts, Janoski said. You may do more harm than good by trying to brush the snow off, because the cold temperatures may have made the wood brittle and easily breakable. “Go for a brisk winter walk outside, and let your shrubs recover by themselves,” she said.
Take care with salt. Salt and other products for melting ice can dry out the tissue of plant stems and roots. “Use as little possible, just enough for safety,” said Sharon Yiesla, plant knowledge specialist. “Don’t spread salt instead of shoveling.” When you shovel snow that may contain salt, try to dump it onto a patio or other paved area rather than at the base of trees or in beds or lawns. “When snow melts, you don’t want that salty water soaking into the soil around your plants’ roots,” Yiesla said.
Be wary of warm spells. The biggest danger to plants in winter isn’t cold, Janoski said. It’s sudden temperature swings, from bitter cold to sudden warmth and back again. “Unfortunately, temperature swings are pretty common around here,” she said. Freeze-and-thaw cycles can crack thin bark on young trees, push perennials up out of the soil or trick plants into sprouting or flowering prematurely. “The best preventative measure is a layer of mulch to insulate the soil, so plants don’t respond to short-term changes in temperature,” Janoski said. If you didn’t spread mulch in autumn, a good layer of snow will have the same insulating effect.
Watch and take notes. There’s not much you can do now to mitigate the effects of winter weather on plants, Janoski said. Most preventive measures, such as spreading mulch or arranging burlap, need to be installed before the harsh weather hits. “What you can do is pay attention to see if any plants suffer,” she said. “You can make plans to protect them next fall or to replace them if a Chicago winter is just too tough for them.”
For tree and plant advice, contact the Plant Clinic at The Morton Arboretum (mortonarb.org/plantadvice, 630-719-2424 or [email protected]). Beth Botts is a staff writer at the Arboretum.