Can I Save My Frost-Damaged Plants?

One night, the temperatures plunge without warning. At dawn, frost sparkles under the early light, outlining each leaf and twig in shining white. It's a strange and beautiful world, shimmering and remote.

It's also a gardener's nightmare. What will happen to the garden plants? Within hours, their foliage is black or brown, their stems shriveling. Can those frosted plants be saved?

The answer, as with many gardening questions, is a cautious "Maybe." Some plants are so sensitive to cold that even a touch of frost will kill them immediately. Others are so tough that, even if their foliage is completely dead, they will grow back from roots that have survived safely underground.

A large number of plants fall somewhere between those extremes, and their fate lies in the gardener's hands.

Act fast!
Frost freezes the water in the plant's cells, which damages the cell walls. The damage is greatest when full exposure to strong morning sun makes the plant defrost very rapidly, because then the cell walls are ruptured.

You can minimize damage by moving the plant out of direct sunlight until it has defrosted. If you can't move it, protect it from sunlight by covering it with a sheet of black plastic for a few hours.

Lightly misting or spraying the foliage before the sun reaches it is another method to protect the plant from the damage caused by rapid defrosting.

Continue care.
If you're leaving the plant in the same spot, don't prune out the damaged leaves and stems until spring. If another sudden frost comes along, the dead foliage will give some protection against further damage to the living part of the plant. Also, you don't want to encourage new growth too soon, because it is more likely than old growth to be injured by another frost.

If you're moving the plant to a more sheltered location or indoors, you can prune away the dead part immediately. It's possible to dig up small plants and move them into a greenhouse or into your house until the cold weather has passed.

Make sure the plant is watered regularly, but don't drown it. Frozen or damaged roots don't take up water as easily as they did before, so it's easy to overwater a recovering plant.