When many plants turn brown or leafless, evergreen trees and shrubs become highly valued as they stand boldly in the Midwestern winter landscape. These trees appear sturdy against harsh snow and wind but can easily be harmed by winter conditions. Steps taken now can help assure your valuable evergreens make it to spring still green and healthy.
The most dramatic harm to evergreens is windburn, which leaves the trees rust-colored and crispy. While the wind certainly plays a role in this, sun scalding is also a factor. Think of it as the evergreen version of chapped lips. The sun and wind dry out the needles faster than the tree can rehydrate them.
Smaller trees and bushes can be shielded with burlap to break the wind and shade the plant. An easy way to do this is by making a V-shaped burlap fence, with the bottom of the V facing west, the south and north sides of the plant covered by the two sides, and the top of the V open. Remember, evergreens stay alive all winter, so don’t wrap them up like a mummy.
Also critical to winter survival is keeping the tree or bush well-watered in November until the ground freezes. The moisture the plant stores during this critical time is what helps hydrate the needles and leaves prior to the soil freezing. Also, water during warm, dry spells, when the soil thaws. Anti-desiccant sprays to coat needles are sold, but people frequently forget to reapply throughout the winter, rendering them less effective. Plus, they are difficult to apply to large evergreens, unlike a good watering.
Heavy, wet snow can cause damage to weaker rounded evergreens, such as arborvitae. To give added strength, tie the top part (often made up of two branches) together on conical-shaped trees. Since evergreens are often planted near the foundation of the house, look up at the roof and assess whether large piles of snow might fall on shrubs.
The weather is not the only force of nature that can bring harm to evergreens. Hungry animals can cause quite a bit of damage as well. The only sure bet is to ring the tree or shrub with a 6- to 8-foot fence, or to cover it with bird netting.
By taking action now, you can assure that your evergreens survive our harsh winters and make it to spring healthy, green and intact.
Jim Stendler is a University of Illinois Extension master gardener for Kane County. The “Learning to Grow” column runs weekly during warmer months of the year. Call the extension office at 630-584-6166 for more information. Feedback on this column can be sent to firstname.lastname@example.org.