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.
