In addition to protection from snow, ice and salt damage, some landscape plants need further care during the winter.

Trees such as maples, crabapples and sycamores often have long, vertical cracks in their bark, usually, on the southwest side of the tree. These "frost cracks" occur on young trees on a cold but sunny winter day when the sun is at its winter peak in the southwest sky. The smooth, dark bark absorbs the sun's rays and expands but the shaded bark on the other side does not. The resulting pressure cause the bark to split.

To avoid this problem, keep the trunks of young, dark barked trees covered with a light colored wrap until the bark matures. Re-wrap the tree every few years to avoid girdling.

Wraps will also help prevent another common winter problem: mouse damage. Mice will eat the tender young bark of trees during the winter. Use a wrap or mesh wire barrier to keep mice away from the trunk. Also, keep mulch, straw, weeds or other materials where mice can hide from accumulating around the trunk of trees.

Broadleaf evergreens include such plants as rhododendrons, azaleas and boxwoods. Since they maintain their large, fleshy leaves through the winter, they face special problems in our climate.

During winter, when the ground freezes, these plants are unable to absorb water into their roots. On sunny but cold days, the leaves warm enough to begin transpiring i.e. they begin to lose water. When the frozen roots cannot replenish this supply, the leaves wilt. If the resulting desiccation is too severe, the leaf will die.

To minimize this problem, keep broadleaf evergreens watered until the ground freezes. Provide a site which is sheltered from prevailing winds by using nearby plantings or constructing temporary windbreaks.

Chemical anti-transpirants may be effective in stopping the water loss from broadleaf plants but they are often difficult to use. The products tend to wash off and must be reapplied during the winter. The weather does not always cooperate for proper application.

Note: We have provided some general information and observations on this topic aimed at the home gardener. Before you take any serious action in your landscape, check with your state's land grant university's Cooperative Extension Service for the most current, appropriate, localized recommendations.


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