Salvaging Winter-Stressed Plants
Wondering if your landscape survived winter’s chill? The impact of cold injury can vary greatly in a neighborhood or even a single yard. When winter packs a wallop, it can be tough to know if plants survived. Discover easy steps to take in spring to determine if things are alive, along with tips for reviving your landscape to look its best.
Look for life. On trees and shrubs, buds swell. For roses, stem color changes. Brown dormant stems shift to burgundy, followed by green. With perennials, watch for new growth to appear in the center of the plant. For woody plants, you can use the scratch test. “This is a good test for young trees planted in the last year or two,” says Alec Charais, Marketing Manager at Bailey Nurseries in Newport, Minnesota. “Before buds break open, gently scratch the outer bark on a twig and look for green tissue beneath.” Green signals life; dark brown or gray indicates death. “Brittle twigs that snap instead of bend are more likely dead,” Charais adds.
Be patient. This is the most important step in determining the status of your landscape. “Wait time varies by plant,” Charais says. “Don’t give up on a plant until other plants in the landscape have developed a flush of new growth. Even then, after a really hard winter, it’s best to wait a few more weeks.” You can also look for similar plants in nearby landscapes to see how they’re faring. Some woody landscape plants resprout from roots after aboveground growth dies. This group includes Endless Summer hydrangea, crape myrtle, butterfly bush, lilac and own-root roses. A few woody perennials don’t typically resprout from roots, such as lavender and rosemary. If these plants show dead top-growth, you should plan on replacing.
Add some food. “For hardy perennials or shrubs, apply slow release garden fertilizer or compost,” Charais says. “If a plant is struggling, a small amount of fertilizer can help it along.” Use a basic 10-10-10 fertilizer at recommended rates.
Prune the dead. When a shrub has a few dead branches among new growth, remove the dead. “It’s always wise to remove dead tissue,” Charais says. “The plant may look odd, but let it grow and flush out. In midsummer, even out growth with a light pruning to shape the plant.” Plants that respond well to this type of pruning include boxwood, dogwood, dwarf burning bush and many hedge plants.
Remove winter burn. Holly and boxwood often emerge from a harsh winter with bronzy leaves, which are suffering from winter burn. “If bronze leaves are on the outer edges of the plant, a light pruning is all you need,” Charais says. “Usually you’ll find green growth underneath. If you have just one odd branch, reach in and clip it out, then shear the entire plant lightly, and it should recover.” When winter burn envelops more than 50 percent of a plant, consider replacing it. To ensure a full recovery from winter burn, fertilize plants in early spring and provide good moisture through the growing season.
Consider replacements. Do some homework before replacing dead plants. A harsh winter typically takes out plants growing in less-than-ideal conditions. “Choosing replacement plants rated for your hardiness zone is important, but making sure you’re providing the right growing conditions is equally important,” Charais says. “Talk to a local garden center about your site and explore plants that fit those conditions.” If you love a plant that’s marginally hardy, tuck it into a container that you overwinter indoors.