Lengthy, windy winter may have damaged your evergreens

The winter damage to evergreens continues to become more visible in gardens and the damage may continue to worsen once there is an extended period of warm weather.

Your evergreens will likely recover if the damage is only on the exterior foliage and there is healthy green foliage deeper in the plant. The plants may still be in trouble if the remaining foliage is starting to dry out while still having green color.

Scratch the bark on a few stems to see if there is any green color under the bark. Any branches that are off color and have bark peeling off the lower stems are likely going to die.

• Volutella blight on boxwood looks similar to winter damage, with leaves turning orange to bronze and then straw colored. The volutella fungus infects wounds in the branch bark caused by winter injury.

The bark at the base of an infected branch will get loose and readily peel off from the gray to black discolored wood beneath. Prune out infected branches and remove any dead leaves under the plant.

Spray pruners with Lysol disinfectant between plants to prevent spreading. Fungicide applications may be necessary to save plants in some situations.

Fortunately, I have not seen much volutella blight in boxwood over the last couple of years. Call the Chicago Botanic Garden's Plant Information Service, (847) 835-0972, for recommended fungicides and timing for applications.

• Improve the health of your lawn by core aerating. Leave the plugs on the lawn, as they will break down in a short period of time.

Aerate before applying any spring pre-emergent herbicides, which form a barrier at the soil surface to prevent weeds from germinating. Pre-emergent herbicides will also prevent grass seed from germinating, so coordinate any seeding with use of a pre-emergent herbicide.

• Many shrubs have been damaged by rabbit and vole feeding over winter. Stems and branches that have had all the bark around them eaten will most likely die above the damaged section, as food and water will no longer be able to move between the roots and foliage of the plant.

If the damage goes partially around the stem, then it may heal and continue growing. The more bark that has been eaten from the stem, the more likely the stem will die above the damaged portion. If you are unsure about whether or not to prune it back, then give the plant time to leaf out and see how it does going into early summer.

Cutting the plant back now, though, will likely give better results for new growth coming from the base of the plant.

• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.