This thought might not have been at the top of your list right before Christmas, but it was on mine – how will the cold snap affect our landscape plants? The best answer I can give today is that we will have to wait and see.
We are likely in better shape than those in the south. The temperatures the week or two prior to the cold snap were seasonal and consistent.
According to the Ohio State University College of Food Agriculture and Environmental Sciences Weather System at the South Charleston branch, the average temperature from Dec. 1 to Dec. 26, 2022, was 31.3F and the historical average temperature is 31.9. Thus, we had average temperatures.
My friends in the south were not so lucky. In Nashville for instance, Facebook friend Troy Marden noted it was 53F at 3 p.m. and dropped to 0.0F at 3 a.m. And of course, if you go further south, the plants don’t tolerate 21F temperatures and will likely be killed if they weren’t protected.
Our plants had more time to acclimate to the cold temperatures than those down south. A sudden drop is much worse than a slow acclimatization. Our plants had time to harden off and shut down for winter. Theirs did not.
We also had a slight snow cover that might help us as well. On the other hand, be on the lookout for rabbits and other rodents eating the tender bark of young trees if the snow sticks around for a long period.
We might see desiccation of evergreens, especially due to the sustained winds. As the wind moves across the foliage of evergreens, particularly broadleaf evergreens such as boxwood, it draws the moisture out of the leaf.
The resulting damage is leaves turning brown and eventually dropping. This may not happen until spring, however. So again, wait and see.
Due to extreme cold, we might also see branch or twig damage to young trees and newly established plantings. If these plants went into this period in stress (dry), there may be damage. On the other hand, because we eased into the cold temperatures, they may be fine.
We might see damage to certain plants that don’t tolerate extremely cold temperatures. However, it depends on how cold it was in your landscape. In 1994, when it dropped to -29.2F on Jan. 19, we saw significant damage to roses, weeping cherry trees and boxwood.
If you read my column regularly, you know I strongly recommend plants go into the winter healthy and with moist soil. Those plants that weren’t so healthy this past season may suffer from this cold snap.
I don’t expect any perennials to be damaged unless they have woody stems which may be killed. We will have to wait and see on roses.
Right now, there is nothing to be done. Wait until buds start to break in the spring and see what happens. Most of the time, pruning dead wood will help encourage new growth. That is, unless the entire plant was killed.
Again, it’s hard to predict what might have happened but I can speculate.
Happy New Year to all and I truly appreciate you reading my column and your emails and questions.