Protect in-ground plants from freeze by draping them with bed sheets, burlap or newspaper — all of which allow moisture to escape, but keep the cold air from making direct contact with the plants.
Freeze events in San Antonio are few and far between, but when they do occur it’s important to be prepared to protect your most vulnerable plants. A healthy plant, one that's been watered appropriately and has a well-developed root system, stands a better chance of surviving freezing temperatures than a distressed plant.
Soft woody plants, active bloomers and potted plants, in particular, are more susceptible to freezes than others. Potted plants can be moved to a protective space, but for in-ground plants good preparation is the key to survival in the event of a freeze.
The first reaction by many is to water plants just before a freeze. This is a misconception. Extensive watering 12 to 24 hours ahead of a freeze is not proactive or protective. Bed sheets, blankets, burlap or newspaper to drape and protect plants are helpful and can protect your plants. There are commercial coverings designed to do the same thing, but they’re much costlier.
Though plastic is also an option, it’s not recommended by many experts because the material doesn't breathe and traps moisture which may compound the freezing problem if cold temperatures persist. You would also need to make sure the plastic does not make contact with the plant. If it does, the plant will freeze.
Using a fabric covering allows moisture to escape and keeps the cold air from coming in direct contact with the plant. Bed sheets work well for protecting large plants and shrubs, newspaper and even small volcanoes of mulch can be used for smaller, low-to-the-ground plants. Remember to remove these coverings promptly after the freeze notice has passed as too much is a detriment to the plant.
Freezes in San Antonio may be rare, but with a little forethought your plants and your mental well-being will not only survive but thrive.