Trees and Shrubs Require Winter Prep
Tips from a certified arborist to keep your living investments healthy
by Peter R. Landau, ISA Certified Arborist
Winter weather can damage landscape plantings. Freezing
temperatures, wind, and winter sun can
Temperature extremes and fluctuations can harm
plants. Typical winter injury is desiccation of foliage due to moisture loss
when the soil is frozen and plants cannot replace the moisture that was lost
through transpiration. Browning and in some cases dropping of foliage in early
spring are signs of damage.
Antidesiccant treatments protect evergreens from
sun and wind overexposure by sealing in moisture. Water plants before soil
freezes and apply a layer of mulch around trees to maintain soil temperature
and retain moisture. Wrap susceptible trees in burlap during winter to reduce
loss of water through the leaves.
Trees are deceived by the warm temperatures of
late winter and emerge from dormancy, only to have tissues killed when winter
temperatures return. In broadleaves, freeze damage can be recognized by reduced
leaf area in the crown, branch tip dieback, clumped leaf growth, or death of
the main stem with new sprouts growing from the base of the tree. In
evergreens, symptoms include loss of buds, drooping of branches, lack of new
growth, and dieback. There is no protection from this injury, however well
cared for trees and shrubs recover faster.
An early frost in the fall or late spring frost
when plants are actively growing may damage plants, causing leaves and shoots
to be injured or killed. Most healthy trees recover from this damage. Years of
repeated frost exposure reduce growth as energy is used up to replace damaged
tissues.
Some tips for protecting your trees and shrubs
include:
• Plant tree species hardy to conditions in your
area.
• Cover young trees if frost is expected.
• Avoid planting in areas subject to frost.
• Don’t apply high-nitrogen fertilizer late in
the growing season.
Thin-bark trees or transplanted trees are most
affected by sunscald. Direct sun during midwinter heats south or southwest
facing bark to above freezing, causing cells to become active. When the sun
sets or bark temperature drops with changing weather conditions, the active
tissue is frozen and killed. Patches of bark crack and fall off, forming a
canker. Cankers are susceptible to insect infestations and disease during the
next growing season.
Wrap the trunks of susceptible trees or shade
them in winter to help prevent sunscald. Cracks or bulges on trunks begin at
the site of wounds or branch stubs. Sudden drops in temperature can cause the
outer layer of the trunk to contract faster than the inner layer of tissues,
leading to an extended crack.
To decrease the chances of developing cankers,
avoid wounds to the trunk and properly prune branches to prevent the formation
of cracks. Wrap the trunks of young trees with paper tree wrap to prevent
cracks.
As food supplies are reduced, rodents and deer
may turn to the new stems or bark of trees for their next meal. This feeding on
the plants can cause them to weaken or die. Damage control measures could
include repellents, physical barriers, and ultrasonic protection.
Those plants that are properly selected for
their site and well maintained throughout the season will fare best through the
winter. A few good tips to follow include: good cultural practices, watering
during dry periods, controlling insect and disease issues, and tying plants
such as yew, arborvitae, and juniper that may be damaged by the weight of snow.
Have your trees inspected each year by a
qualified arborist. To locate a qualified arborist in your area, visit
treesaregood.org.
Posted by Chris Hewitt
on 9:37 AM.
Filed under
Environment,
Feature,
Lifehacker
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