Regardless of where you live in Georgia, cold damage to ornamental plants can cause major problems in your winter landscape. There are a few preventative measures that can be taken to help reduce the chances of cold damage.
During the late summer and early fall, plants begin preparing themselves for winter. This process is called “cold acclimation.” It is initiated by the cooler temperatures and the shorter day lengths.
Cold acclimation must occur in a timely fashion. If it occurs too early, the growing season of the plants will be shortened; if too late, they will be injured or killed by early frosts.
Several factors including local weather conditions, plant selection, and maintenance practices during the growing season, can affect the timing and extent of cold acclimation of landscape plants.
The best way to prevent cold damage is to select plants that can tolerate temperatures in your climate zone.
In addition to plant selection, proper site selection is essential. Assess your property to determine the coldest and warmest spots. During the winter, warmer spots are often found on the southern part of the property and colder on the northern. Cold air also will settle in low areas.
Maintaining proper plant nutrition increases a plant’s ability to tolerate cold damage. Fertilizing plants at the proper time of year is also vital. Fertilizing plants in the fall with nitrogen can cause a flush of new growth that is more susceptible to cold temperature.
Pruning in late summer or early fall can cause a flush of new growth that is more susceptible to cold damage. As a general rule of thumb, spring flowering plants should be pruned after they flower in the late spring; summer flowering plants should be pruned in late winter/early spring. Plants transplanted in late fall or early winter are more susceptible to cold temperatures. Always transplant in early fall.
Plants’ canopies can help reduce heat loss from plants and soil by preventing heat loss to the atmosphere. Windbreaks are useful in reducing injury caused by cold winds and advective freezes.
You can protect plants in containers by moving them into a protective structure or by placing a cover over them. Plants in containers are especially susceptible because their roots are more exposed to air temperatures. Containers left outside can be pushed together and covered with mulch, burlap or a blanket to reduce heat loss. Plastic sheeting is not recommended; the plant can heat up rapidly as the temperatures rise during the day. Remove the cover and provide ventilation to the plant during the day. You can build a frame to keep the cover from coming in contact with the plant and possible breaking leaves and stems. Plants growing close to the ground are usually protected by heat radiating from the soil.
Plants continue to have water needs throughout the winter. Also, moist soil absorbs more heat. Cold damage may not be apparent for several days or weeks. Cold damage will cause discoloration to the damaged area. Wait to prune any damaged tissue until after the threat of a freeze has passed to protect possible live tissue.
For more information on any program area, contact Houston County Extension at 478-987-2028 or drop by our office in the old courthouse, downtown Perry, 801 Main St. Office hours are 8 a.m.-5 p.m., Monday through Friday. Visit our website at www.caes.uga.edu/extension/houston/ for more news about your local Extension office.
DATES TO REMEMBER
Dec. 25-Jan. 1: Extension Office Closed for Christmas Holidays.
Jan. 5-7: Beltwide Cotton Conference San Antonio.
Jan. 15: Georgia Peanut Farm Show, Tifton.
Source: UGA Publications: Winter Protection of Ornamental Plants, Robert Westerfield