WITH FROZEN PLANTS, ‘LET IT GO’ UNTIL SPRING, by Sheila Dunning UF/IFAS Extension Agent

cold_damaged_plantNorthwest Florida’s winter temperatures are frequently low enough to cause cold injury to tropical, subtropical and occasionally temperate plants not adapted to our state’s climatic conditions. Then the weather warms and you feel compelled to do something about it.

However, keep in mind: Florida landscapes’ root systems are seldom “frozen.” Many plant parts adapt to tolerate low temperatures. The cold never bothered them anyway.

Remove this, keep that

While dead, unsightly leaves may be removed as soon as they turn brown after a freeze, remaining dry-looking stems serve as food storage and should be allowed to remain. If they are removed before the weather warms enough for the plant to resume growth, the root system may not be enough to support the plant, and it will die.

So, here’s the lesson from Disney’s “Frozen”: “Let it go, let it go, let it go.” “The perfect” landscape” is gone.” “The past is in the past.”

Tropical plants and summer annuals do not adapt or harden to withstand temperatures below freezing, and many suffer injury at temperatures below 50 degrees Fahrenheit (10 degrees Celsius). Subtropical plants can harden or adjust to withstand freezing temperatures and, properly conditioned, temperate plants can withstand temperatures substantially below freezing. Recently planted, not-established plants may be more susceptible to cold injury.

Injury types

One type of winter injury is drying out, characterized by marigianl or leaf-tip burn in mild cases and totally brown leaves in severe cases. Desiccation occurs when dry winds and solar radiation result in the loss sof more water from the leaves than can be absorbed or transported by a cold root system. Plants can lose substantial moisture during a windy freeze, so check their water. Plants will lose water vapor on a sunny day after a freeze.

To identify cold-injured wood, lightly scrape the bark with your fingernail and examine the color of the cambium layer (food conducting tissue) just underneath. Green tissue indicates the plant is still alive at that point; black or brown coloration indicates dead or injured tissue.

After a particularly harsh cold event, some plants may be very slow to recover, so some patience is required. “It will rise” with “the break of spring.” Branch tips may be damaged while older wood is injury-free. Delay pruning until new growth appears next spring to ensure that live wood is not removed.

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