We plant evergreens for their graceful beauty and magnificent color that breaks up winter’s white and drab brown. This beauty and color come with a price. In winter, evergreens are exposed to winds that can dry them out and cause branch dieback. The dieback appears as brown patches on an otherwise green tree or shrub.
Unlike deciduous trees and shrubs that go dormant in winter, evergreens continue their bodily functions, although at a much slower pace. This includes photosynthesis, which depends on water and nutrients from the soil reacting with the sun’s energy to make food that’s stored in the plant’s root system until it’s needed elsewhere in the plant.
Water and oxygen are byproducts of photosynthesis. The oxygen is released into the atmosphere for us to breathe and water is released through the plant’s leaves or needles. This release of water is called transpiration.
When the ground freezes in winter, roots can’t absorb water from the soil. The plant then depends on reabsorbing transpired water back in through the leaves or needles. High winds, however, blow the water off the leaves or needles before it can be reabsorbed, causing the leaves or needles to dry out. This is called desiccation.
Desiccation can be minimized by spraying a wax like substance, called anti-desiccant, on your evergreens. The most popular brand name is Wilt-Pruf. You can buy it in spray bottles at garden centers if you have only a few evergreens to spray. We use a backpack sprayer to apply antidesiccant to properties with greater needs, such as large evergreen trees or many evergreen shrubs.
When deciding on how many evergreens need spraying on your property, include broadleaf evergreens, such a boxwoods and rhododendrons, as well as conifers. With more leaf area, broadleaf evergreens tend to transpire more water than conifers.
Tender trees, especially young trees that you just planted this year, may need a burlap coat, as well as anti-desiccant. Just drive poles into the ground around the perimeter of the tree, wrap with burlap and staple it to the poles. Be sure to keep the top open to moisture and sunlight. Wrapping may also be needed for trees planted close to the road to protect them from road salt spray.
Anti-desiccant is one of the most economical insurance policies you can buy to increase the survival rate of evergreen trees and shrubs. You should plan ahead, however, since there is a relatively short application opportunity. It has to be applied when the temperature falls below 40ºF but after the chance of warm days passes since warm days can melt the material. You can buy anti-desiccant at the garden store now and hold on to it until needed. If you want us to apply it, you should call now so we can schedule the application.