Risk of Frost Damage in the Atlanta Landscape

Risk of Frost Damage in the Atlanta Landscape

Posted by on Jan 19, 2018 in Landscape

Risk of Frost Damage in the Atlanta Landscape

There is a high risk of frost damage in the Atlanta landscape this winter. The metro Atlanta area, especially the Buckhead area and the northern suburbs, has been shocked with extraordinarily low temperatures, snow and ice. Normally, most of our plants can handle a bit of severe winter weather. This year, however, the particular set of weather circumstances created a perfect storm for frost damage in Atlanta landscapes.

Unlike our residents, most of the plant material in the Buckhead / Atlanta landscape is capable of handling 12 to 15 degree temperatures without significant frost damage. This year, however, has a much higher risk of frost damage due to the fact that we are coming off one of the longest summers in our history. Our October temperatures hovered near 90 degrees early in the month, and our average lows in November were a balmy 42 degrees.

Why, you may ask, does a warm autumn affect frost damage? Because these warm temperatures kept our grasses, plants and trees from preparing for winter. Some were still sprouting new growth at Thanksgiving when they should have been shutting down for the winter. If December stayed mild and we would have gradually worked our way down to the freezing mark, all would be good. Instead, December came with a vengeance and our low temperatures dropped like a rock from the 40s to the low teens. Those plants and trees, many still green and growing, suffered quite a shock from such an extreme and rapid temperature swing. Historically, by the time the Atlanta landscape sees temperatures in the teens we have had weeks, if not months, of temperatures dipping into the upper 20s. This winter we went from the low 40s to the low teens in a matter of weeks.

So what can you do to minimize the damage? First and foremost, don’t over-react. Remember this about garden maintenance and lawn care: Every application, treatment or cut temporarily adds stress to plant material. So your best immediate response is no response at all. Suspend everything until we reach seasonal temperatures – no fertilization, no weed control, no lime applications and no pruning**.

Second, make sure you water before the next round of harsh weather. A well-watered plant is far more resilient than a drought-stressed plant. We would like to think we won’t see any more temperatures in the teens, but that’s just wishful thinking.

**Since the most important pruning of the year takes place in winter, you may wonder why we suggest not pruning now, so keep reading. We’ll tell you.

Cool Season Grasses (Fescues)

This has been a terrible year for Fescue grasses. Fescue is a cool-season grass, grown for temperatures between 50 and 85 degrees, and we haven’t had many days between 50 and 85. Because of the extremely hot fall, the window to re-seed Fescue was short and didn’t give the newly-seeded grass to mature before temperatures plummeted into the teens.

To repair any frost damage to Fescue lawns, carefully re-seed the damaged areas in the February timeframe. If you have a landscape service, they will probably do this automatically. February is early and temperatures will still be low, but you want to get some germination going as much before spring as possible. Be careful not to put down too much seed. Yes, you can put down too much seed and it will never perform well because the grass will be too crowded. “More” is not always “better”. It takes a long time for seed to germinate this time of year, so don’t add more seed a week later thinking your first application washed away.

Warm Season Grasses

Warm season grasses like Zoysia and Bermuda can generally withstand temperatures of 10 degrees or so and suffer only minimal frost damage. But when temperatures are in the 80s in October, warm season grasses think its still summer. Instead of gradually shutting down for the winter, they stay green and keep growing. These grasses are most sensitive during the transition into and out of dormancy and during this sensitive period, these grasses were shell-shocked with temperatures in the low teens.

Since these grasses are now dormant there is nothing we can do to assess or repair the damage. Perform your usual pre-emergent applications but other than that, leave them alone. In spring you can begin to assess the damage and begin the repair process. Minor damage can be raked out, fertilized and watered generously and the grass will repair itself with a little time. More extensive damage may need to be cut out and patched with sod. If you go this route just make sure you know what kind of grass you have. Patching Bermuda with Zoysia, or worse, Zoysia with Bermuda, will give you a major headache.

Plants, Trees and Shrubs

With such extreme temperature swings we could see frost damage throughout the Atlanta landscape. With the extremely cold temperatures and the amount of snow we have already seen, even Pansies will be impacted. Your first priority in a frozen garden is to make sure you don’t do more harm than good. Don’t recklessly knock the snow of Pansies, Boxwoods or even trees. Remember, in freezing temperatures plants are brittle and branches can snap. Most important, be careful not to slip on ice or snow and hurt yourself. Whatever damage there may be is already done and rushing out to prune a branch or knock the snow off isn’t going to make it better.

Here is where some good news comes in. Winter is the best time to prune just about everything! And with proper pruning you can cure almost all ills, including frost damage. It is almost the time to begin, but earlier we suggested you wait for a bit longer because we prefer to start our heavy pruning in early February. With the bizarre weather we experience in the Atlanta area, waiting until February gives us a little more confidence that dormant plants and trees are truly dormant.

Soon you can begin all of your winter pruning. Use these cold winter months to keep your foundation plants in scale or just to keep them healthy and flowering. This is also the time to rejuvenate plants that are damaged or unhealthy. Many can be pruned to one or two feet tall, after which they will come to life as a healthy, full, new plant. The winter is the time for all of your rejuvenation pruning, but make sure you know your plants and you ask, like how I would ask for a tree service near me, before you embark on something like this.

Happy gardening. And remember, in the garden be bold when it’s cold!