Sure, trees go dormant during the winter, but that doesn’t mean they don’t need any help from you, especially young trees. Stress from severe winter weather (extreme cold, harsh wind and bright sun) can cause bark splitting and separation of the tender new wood just beneath, as well as dieback and browning of leaves. Winter damaged trees are also more vulnerable to attack by disease and insects. Follow these guidelines to prepare trees for the winter:
Mulch around the trees, as described earlier. Mulches protect the soil from the effects of freezing and thawing, which disturbs shallow tree roots.
Water deeply just before the ground freezes. Use slow drip irrigation to help fight winterkill.
If a young evergreen tree or deciduous tree is located where heavy winds are common, set up windbreaks around evergreen trees using some stakes and natural burlap. If you don’t have burlap, white polyspun floating row cover makes a good substitute. Snow fencing also makes an excellent wind barrier. Avoid using plastic sheeting. It prevents air circulation and concentrates heat from the sun.
For evergreens, an optional step is to spray evergreen foliage with an anti transpirant spray. This product forms a clear, flexible film on plant surfaces, thereby reducing evaporative water loss by up to 80% while allowing gas exchange. As a bonus, it prevents fungus spores from becoming established on the foliage, thus cutting down the risk of disease. Apply when the air temperature is above 40° F and before the ground freezes hard. Anti transpirants are available at garden centers.
If you have young trees and we get a snow accumulation of more than 3 inches, you might want to clear the snow away from the base of each of those trees to keep mice or voles from tunneling under the snow cover to chew on the bark.