In my humble opinion, anti desiccant is the most economical protection against winter burn that you can provide for your evergreen trees and shrubs. That’s why I remind you of it every fall and encourage you to plan ahead for its application.
Anti desiccant’s application is very weather dependent. It can’t be applied when the temperature is too high or too low. It’s a wax-like liquid. Consequently, it can freeze when it’s cold and melt when it’s warm. We apply anti desiccant on days when the temperature is below 50ºF and above 32ºF (freezing). If we get sustained warm spells during the winter, additional applications may be necessary. Nothing needs to be done in spring, though. The anti desiccant just melts when the weather warms up.
Why apply anti desiccant? Unlike deciduous trees and shrubs that go dormant in winter, evergreens just slow down their life functions. This applies to both needled conifers like pines and broadleaf evergreens like rhododendrons.
Evergreens’ leaves or needles continue to manufacture food through the energy trapping process of photosynthesis. That process requires water, which is normally absorbed by the roots and transported to the leaves by the plant’s xylem. Water, also a byproduct of the process, is given off through the leaves. This is called transpiration.
When the ground is frozen, the roots can’t absorb water, so the plant reabsorbs transpired water and recycles it during photosynthesis. This is fine until the wind blows. Wind picks up transpired water droplets and carries them away before they can be reabsorbed. When this occurs, photosynthesis shuts down and the affected leaves, needles and branches die.
Desiccated leaves and branches turn brown but the whole plant rarely dies. It just has ugly brown patches, and the only remedy is to cut out the deadwood. This affects the aesthetics of an otherwise graceful, beautiful evergreen.
Evergreens provide winter interest to your landscape. The various textures and shades of green break up the otherwise desolate sea of white that greets you when you go out the door or look out the window. It’s also a much more interesting view than that of tan shrouds where your evergreens stand in summer. Before anti desiccant, it was common to wrap all evergreens in burlap. Today, only plants affected by salty road spray, young trees and shrubs that are still getting established, or tender plants that may be near the limit of their hardiness zone benefit from wrapping. The others are sufficiently protected by anti desiccant.
Garden centers and home stores sell anti desiccant in spray bottles. The most familiar brand is Wilt Pruf, and it’s in easily recognized green bottles. Buying one or two of these bottles to apply to a couple of evergreen shrubs is a good DIY project. Any more and your hand will let you know how hard it is to squeeze those spray triggers.
For properties with many or large evergreens like towering conifer trees, it’s more economical and efficient for one of our Plant Health Care professionals to apply anti desiccant. We buy it in bulk, which is considerably less than buying those consumer-size containers at retail, and you don’t have to worry about properly disposing of the empty containers. Our PHC pros apply anti desiccant with backpack sprayers that have enough pressure to reach the tops of tall trees.
You planted evergreens to enhance your landscape 12 months a year, and anti desiccant is the most economical insurance policy you can buy to protect them during our severe winters.