Prevention and Care of Freeze Damage
On a night when a freeze is predicted cover the plants as soon as
you can, ideally before sundown. Plants should be covered with
materials specifically for this purpose, such as frost blanket, or
with sheets, blankets, burlap, etc. Match the weight of the
material to the size and sturdiness of the plant, or use a frame to
hold the weight of the material. Never use plastic to cover a
plant directly, or let parts of the plant touch plastic, as it will
freeze at the point of contact (unless this is plastic especially
made for frost protection).
Remove all coverings, other than frost blankets, the next morning
once the sun is up and the temperature is above freezing. If
several nights of freezing are expected the frost blanket can be
left on for up to a week, often longer, depending on the type used.
SYMPTOMS:
Freeze damage on woody plants is usually seen as leaf browning and
then leaf drop, or a blackening of a portion of the stem.
Scraping the stem will reveal whether the stem is alive or not.
Severe freeze damage will result in death of all or part of a stem.
PRUNING:
Regardless of the symptoms of freeze damage, all pruning of affected
parts of woody plants should be delayed until after the danger of
more frost is past. Not only is there increased
risk of infection when pruning before then, but the old plant
material provides protection to areas lower on the plant which may
not have been affected. When pruning freeze damage from a
plant, prune back to healthy tissue. When all the damaged part
of the plant is pruned, look carefully at the plant. Many
woody plants require further pruning at this point for shaping.
Some plants can be pruned entirely to the ground. If you need
or want to prune a freeze-damaged plant entirely to the ground, make
clean sharp cuts leaving about 6” of stem above the ground.
