Recent Freezes Have Left Burned Plants in Their Wake

San Antonio Express News
Sunday, December 7, 2003

By Nathan Riggs

Freeze Burned limbThe past couple of weeks have left many of our local landscape plants burned or frost bitten to the point of no return. At least two nights during Thanksgiving week were below frezing and those two nights were enough to put bermuda and most other warm-season grasses into winter sleep. Many other plants also “took it on the chin” as well. Lantana, firebush, ornamental grasses and other similar plants not protected now have dead leaves and an ugly appearance.

Have no fear! These plants normally freeze back during the winter and will return in spring. Because winter hasn’t even begun, it’s not a good idea to prune these dead twigs back yet. The sap in these plants hasn’t receded enough and pruning now may make the plant even more susceptible to freezing temperatures later on. Be sure to water all plants thoroughly prior to freezing temperatures to allow them some soil protection as well. Remember that roots continue to grow during cold weather even if the plant “appears” dormant.

Time is nearing when trees can be pruned more safely than in warm weather. Oak trees are the one tree that is at the most risk at pruning time due to the presence of oak wilt in the San Antonio area. Oak wilt spores are commonly transmitted from sick trees to healthy ones on the bodies of sap beetles while they visit fresh wounds to feed on sap. Sap beetles are active at temperatures above 60 degrees and can transmit oak wilt during this time. If you must prune oak trees, be sure to spray all cuts and wounds within a few minutes of causing them, to afford as much protection as possible. Spray the cuts with latex spray paint of any type.

The time for transplanting trees and most shrubs is also coming soon. There is much less risk of shock to these plants by transplanting them in winter than during warm weather.

During cooler periods, house-infesting ants also become more visible indoors. Sugar ants, crazy ants and carpenter ants are the most common indoor ants in San Antonio. During the winter, these ants rely more on sweet foods for survival than for proteins to produce new ants. A simple, but effective homemade ant bait can be made by dissolving 2 teaspoons of boric acid powder (roach powder) in 1/4 cup of hot water and adding the solution to 1 cup of corn syrup. Mix well and place small amounts of this syrup bait in jar lids or bottle caps near where ants are observed. This irresistible bait will reduce ant activity within five to seven days. If the bait gets dry, re-hydrate with a few drops of water.

These and many more tips on plants, bugs, and nutritious holiday tips can be found at the Bexar County Extension office at (210) 467-6575 or on the web at

This article was written by Nathan Riggs, Extension Agent – Integrated Pest Management-Bexar County.

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