It was cold. December 23-27 were some very cold days. One of the things that was unique about that cold was how early in winter it got cold, how low the temperature got, and how long the temperature stayed cold. Let’s talk about the cold and the impact that it could have on plants.
All plants have some level of cold tolerance. Some plants have more than others. In perennial plants the amount of cold tolerance that plant has depends on its level of dormancy. Plants that are 100% dormant can experience some very cold temperatures and not sustain any damage when they start to regrow. There are some things that can affect the level of dormancy that a plant has. Fluctuations in temperature affect dormancy. Plants do better in winter if it gets cold and stays cold. When the temperature goes up and down plants can get confused and think that spring is on its way. This is a common issue that we have compared to places further north. Plants that are stressed don’t go into dormancy as easily either. Not enough water, disease, insect pests, not enough sunlight, and age are some of the things that can cause stress on plants. If you have plants that are experiencing stress their dormancy won’t be as deep, leaving them more susceptible to freeze damage. Plants that are not in their correct USDA zone will not handle the cold as well.
Freeze damage occurs when the temperature inside of plants is cold enough for ice crystals to form. This will break plant membranes causing that portion of the plant to dehydrate and die. Because the damage occurs inside the plant it can be difficult to know if your plants have freeze damage. In perennial plants with large trunk and branches you can start to look for splits in the coming weeks, as evidence of freeze damage. Some plants may look fine, but then as we get into summer have large brown patches in them. These are plants that had some damage to their xylem, and were able to grow until summer when their xylem had to move more water because the plant was transpiring more.
So, what can you do if you have freeze damage? The best thing right now is to be observant. Watch to see if your plants start to exhibit symptoms. Depending on the where it occurred the plant might be able to self-prune and remove the damaged tissue. In some situations, it may be necessary to prune some dead wood out of the plant. In either case it is best to wait and let the plant fully show the symptoms before deciding to cut.
If you have fescue in pasture or for lawn, it likely did not sustain much damage. Tall fescue has a waxy layer that protects if from colder temperatures. In fescue after a freeze sugar content increases. This makes it ideal for a stockpiling and winter grazing.
If you have questions about freeze damage contact your County Extension Office or email me at Jacob.Williams@uga.edu.