Winter can be stressful for the evergreens in our home landscapes…but not for the reason you might think. Spruces, pines, junipers and arborvitaes really aren’t troubled by cold and freezing temperatures. But winter does bring other enemies. Take action now to protect your evergreens from these threats—before the snow starts to fall…
Ice and snow. When a winter storm dumps a heavy load, the flexible branches arch and bend. If the temperature doesn’t rise a little and the burden of snow and ice doesn’t slide off within a day or two, branches can break or snap off. This is especially true of evergreens with columnar growth habits such as Emerald Green arborvitae, Skyrocket juniper or a slender Norway spruce.
What to do now: Erect a plywood tent over each tree or shrub…or loosely wrap up each plant in burlap, securing it with twine…or truss it, with the rope hugging the upright-growing branches to the trunk. All these methods work, though I prefer the last because winds can topple or undo the coverings. In winter: Go out after a storm, and use a broom to brush accumulated snow off of heavily-laden branches.
Salt. During brief periods of thawing, salt spread on snowy, icy roads can be sprayed up onto plantings by passing vehicles and melt into the ground. Leaves and needles get coated, and roots take up the salty moisture. Result: You’ll see the growth turning brown or yellow, then falling off. Foliage and even whole branches can be damaged or killed.
What to do now: Erect temporary snow fencing along the walkways and roadways, and dig trenches to reroute snowmelt and keep salt away from evergreens. In winter: Dump water or shovelfuls of untainted snow in the area when there’s a thaw to dilute the salt content.
Drying out. Evergreen needles conserve moisture, and in winter, the plants’ metabolism powers down. But sometimes, especially during prolonged wind, evergreens lose moisture that their roots cannot replace. Occasional mild days also cause leaves to vent off moisture. Broadleaf evergreens, notably rhododendrons, are especially vulnerable. Leaf edges will curl inward in a bid to conserve, but the leaves still may dry out, die and fall off.
What to do now: Give your plants one last good deep watering so they go into winter well-hydrated. Then spray the leaves (both sides) with an “anti-desiccant” polymer or oil, available in autumn where gardening supplies are sold (Wilt-Pruf is a brand name). The spray coats the leaves and helps seal in moisture. By the time the coating breaks down, spring is around the corner.