Although temperatures are beginning to drop, evergreen trees and shrubs continue to require our attention. The dry conditions in our area increase the amount of stress placed on trees and shrubs, including evergreens. To minimize winter water loss and winter burn, ensure evergreens receive adequate moisture. Water all evergreens during dry weather periods, until the ground freezes. Additional watering may be necessary during winter months, as long as the ground hasn’t frozen. Cold days do not necessarily guarantee the ground has frozen. Frozen soil is dense and rigid and does not give way under foot. Before watering, test the soil to determine if it is frozen. Once the ground has frozen, evergreens no longer take up moisture from the soil. Although the amount of water lost during the winter slows, it does not stop completely. Therefore it’s important that evergreens start the winter season with plenty of soil moisture. Dry soils tend to freeze more deeply, therefore increasing the risk of winter damage in the landscape.
There are a few guidelines for successfully watering evergreens:1) Water early in the day to prevent it from collecting around the trunk. Water that hasn’t evaporated by the evening may freeze and damage the evergreen.
2) Most evergreen trees and shrubs require moisture at least 18” deep in the soil.
3) Mulching around the base of the trees and shrubs will insulate the soil and conserve moisture.
Evergreen trees and shrubs located in areas unprotected from winter winds may experience more severe winter water loss symptoms. Consider an anti-transpirant spray application to protect evergreens from winter water loss and winter burn. An anti-transpirant spray limits the amount of moisture lost through the needles or foliage of an evergreen. Winter evergreen enemies, such as wind, sun and salt aren’t as damaging when evergreens are protected. Contact the PHC department for more information on this treatment.