Evergreen trees need water
Q: Last winter I had some evergreen shrubs that had more and more brown needles by the end of winter. Is there anything I can do to prevent this?
— Bill from Salem
A: Unlike deciduous trees and shrubs, evergreens have a continuous need for water during fall and winter. When the ground dries out or freezes, the roots of evergreens can no longer supply water to the leaves or needles and they can begin to die. This results in a condition called winter burn or winter desiccation.
Evergreens exposed to winter sun and wind will have more injury than those in shade.
There are several steps you can take to help your evergreens avoid winter burn. First, keep watering them until the ground freezes.
Water in the afternoon when the temperature is above freezing to allow the water to soak into the soil before it freezes overnight.
If your evergreens are not too big, you can construct a wind break to help protect them.
Also, a little fall mulch will help. Two inches of mulch over the root zone of an evergreen will keep the roots moist and the soil unfrozen for longer than just bare ground.
Most people don’t notice the winter burn damage until the spring when they see the brown, dead looking areas on their evergreens. Depending upon the amount of damage, most winter burned plants can recover in time.
If just the leaves or needles are dead, the plant will eventually grow new ones. If a stem(s) has been killed, it will have to be pruned out. To tell if the stem is still alive, gently scratch the bark and look for green under the bark.
For more information, visit http://go.osu.edu/latefallwater.