Protect Evergreens from Winter Stress

It is now November and although the temperature is supposed to stay in the fifties tonight, the calendar says that freezing temperatures are not far off. This weekend was spent doing fall cleanup, raking leaves, picking up dead branches from the storm Sunday night and spraying our evergreen leaf shrubs with Wilt-Pruf®. I use it on Rhodedendrums, Azaleas, Boxwood and Andromeda. Although these plants are winter hardy, sometimes during severe winters if the leaves are exposed to drying winds and thawing then freezing temperature, this can stress the plant, resulting in brown curled leaves that may not recover in the Spring. Although it may not be needed every winter, to be safe, I apply this spray each year after the temperatures dip below freezing. Since, using it I have not lost any  shrubs due to winter weather. Wilt-Pruf® contains a trademark chemical Pinolene®, a Lewis acid catalyzed polymer of beta-pinene which is derived from the resin of a pine tree. It can be purchased in a spray bottle, or as a concentrate. Also, note that Wilt-Pruf® is not the only brand out there. Bonide sells a Wilt Stop® made from Pinene. Both brands offer a ready-made spray or a concentrate.

Ready made on left and concentrate Wilt Pruf on right.

I prefer the concentrate as it is less expensive and easier to apply with a pump-style sprayer. It is important to apply early in the day as it needs several hours of daylight to properly dry. If you can, it's best to apply on both sides of the leaf surface.

Another way to protect shrubs from winter damage is to wrap them. I do this for our Yew and Arborvitae, but the primary reason is to keep deer from browsing on them. If we get a lot of snow, they will be coming up to the house looking for exposed plants and these two shrubs seem to be their favorite. I use burlap which can be reused for several years. I will do this chore in a couple weeks, after it gets a little colder and before a significant snowfall. I feel a little bad that the shrubs are covered from sunlight for five to six months, but it's better than being eaten.