LEAFLET NO: 604
Revised 9/93 -- Author Reviewed
PROTECTING PLANTS FROM COLD DAMAGE
During the winter months it is necessary to offer protection to
certain North Carolina landscape plants. Winter protection does
not mean to keep plants warm, as this is virtually impossible but
to provide protection from damaging wind, heavy snow and ice,
the alternate freezing and thawing of the soil beneath the plants
and heat from the sun on very cold days.
Department of Horticultural Science
North Carolina Cooperative
North Carolina State University
Protection should be offered to evergreen plants by reducing
water loss. Plants transpire water through their leaves.
Evergreens continue to lose water during the winter,
therefore moisture must be taken up by the plants' roots.
Homeowners are more conscious of watering shrubs during the
summer months and often this garden chore is neglected during
cold weather. The roots will absorb moisture when it is
available but when the ground is frozen or during a dry period
the moisture is not available. The plants continue to transpire
water but at this time draws moisture from living cells. If too
much is given off from this source the cell dies. Consequently
leaves brown out and die.
High winds and a warm sun on cold days result in a higher rate of
water transpiration. Protection could be offered by planting
susceptible plants in a sheltered location and providing
additional water during dry periods or prior to expected hard
Foundation plantings are often injured by ice and snow falling
from the roof on their frozen branches. It is sometimes
necessary to construct a temporary shelter for shrubs in a
Wide tape or cloth can simply be wrapped around an evergreen to
prevent broken branches. This is quite helpful to boxwoods and
arborvitaes. If branches are bent and broken over by heavy ice
or snow it is advisable to wait a few days before pruning and
cleaning up. Often branches will recover to a degree of
satisfaction on their own--so don't be hasty to prune drooping
An additional layer of mulch is usually recommended during winter
months after the first freeze. Mulches will reduce water loss
from the soil thus aiding in transpiration, and also reduce
'heaving' of the soil as the soil freezes and thaws.
To protect plants from cold damage, the following 6 steps are
- Plant only varieties that are hardy to your area.
- If you have a choice, locate less hardy plants in the highest
part of the yard. Cold air settles to the lowest part of the
- Protect plants from cold wind. A fence or tall evergreen
hedge of trees or shrubs gives good protection.
- Shade plants from direct winter sun, especially early morning
sun. Plants that freeze slowly and thaw slowly will be
damaged the least. Obviously, the south side of the house
with no shade is the worse place for tender plants.
- Stop feeding plants quickly-available nitrogen in late
summer. Let them "harden off" before cold weather.
- A covering of plastic is excellent protection. Build a frame
over the plant or plants, cover with plastic and seal plastic
to the ground with soil. Shade plastic to keep temperature
from building up inside. This plastic traps moisture and
warm air as it radiates from the soil. It also knocks off
cold wind. Be certain not to allow plastic to come in
contact with plants.
Repair to Storm Damaged Plants
Knowing how and when to offer first aid to an ice, snow, or wind
damaged plant will often save the plant from future decay and
possible loss. Do not be in a hurry to start pruning a branch
which is bent out of shape. Often in a few days following the
damage the plant will straighten up on its own. Broken limbs can
be pruned immediately. Make clean cuts with sharp tools. If the
plant is completely misshapen after the corrective pruning -
consider pruning the entire plant where the subsequent growth
will be in balance.
Trees can be straightened by cabling or guying. Straighten them
by attaching a cable or guy about 3/4 of the way up - pulling
them back into position. Be certain to pad the tree to protect
against wire damage.
Trees which are uprooted should be immediately straightened and
staked. Remove any damaged roots or limbs by pruning. Keep the
tree mulched and watered during stress periods.
North Carolina Cooperative Extension Service
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