Monday, April 14, 2014

Winter Damage in Colorado Evergreens by Mary Small

Many conifers aren’t looking too great right now. Much of the problem is related to dry fall and winter weather over the last couple of years.  Fall and winter months are typically dry, but these past couple of years have been especially dry.  How does that affect these plants?
Although trees and shrubs “go dormant” in the fall, the root systems of these plants still function as long as soil temperatures hover around 40 degrees.  Roots need water  to function properly and their source for that is either Mother Nature or irrigation that we provide.  No water during this period stresses or kills roots through dehydration. 
Evergreen leaves can continue to transpire, that is, lose moisture to the surrounding environment, on warm sunny days, even in the winter.  This is a normal leaf function, designed to keep the leaves from overheating, kind of like our perspiration. 
The problem this creates during dry or windy fall and winter periods is that evergreens may not be able to replace the lost moisture (if the ground is frozen) or may not be able to replace it fast enough to keep up with the loss. 
The browned needles won’t green up, but new needles will “mask” the damaged ones. If you’re still concerned about the evergreen’s health, gently press a bud (found on the tips of the twigs and branches) between your thumb and first couple fingers.  If the bud feels soft, it is alive and will produce new growth this year.  If the bud is dry and brittle, it is dead.  Check in several places around the plant.
This season, make sure these plants receive water once or twice a month in the absence of rainfall or snowmelt.  Next fall begin a regimen of monthly watering to help roots survive dry weather.