With the unusually cold winter this year, you may have noticed more winter-burn on your broadleaved evergreens and evergreen perennials than you might normally see.
Winter damage appears as drying along the edges of the leaves, the entire leaf, the death of the younger shoots, or even the entire plant.
The damage occurs when the evergreen plant is losing water through its leaves faster than it can replace it from the soil. During the winter, this occurs when the weather is cold and windy, the ground is frozen, and the plant is unable to take up water.
When the weather is warmer, the plant takes up water through the roots so that the leaves are better able to sustain water loss. If the soil is dry and the plant can’t take up water during warmer periods, then the damage is more severe.
How do you prevent winter damage? Water broadleaved evergreens in the fall during dry spells, especially those that are newly-planted. You may need to water once or twice during the winter when the ground is thawed, more regularly if the plants are in containers. Particularly sensitive plants such as camellias should be planted in sheltered locations, out of the wind.
What to do now?
Give the plants a good soaking—water thoroughly. Let the damaged leaves drop; they will be replaced by fresh leaves soon. For evergreen perennials such as hellebores or epimedium, remove the old damaged leaves and stems, taking care not to cut off the newly emerging leaves and/or flowers.
If entire shoots looks dead, scratch the stem with your fingernail. If it is green beneath the bark, it is still alive and may send out new leaves. If it looks dry beneath the bark, like a toothpick, then the shoot is probably dead. Regardless, wait a few weeks to see where new growth emerges before you prune out dead shoots, or pull out the plant. Unless you are an experienced gardener, it’s best to wait until mid-or the end of April before pronouncing the patient dead.
Feel free to cut off a couple of shoots about 6 inches long with some damaged leaves and bring it into the store. We will be happy to look at it for you and tell you whether we think your damage is caused by cold or some other factor.
by Larry Hurley
Photo thanks to the Missouri Botanical Garden.