Winterburn On Evergreens

It’s spring once again, and as homeowners and gardeners across the North emerge from their winter hibernation and venture forth into their yards and gardens once again, they will inevitably notice the ravages of winter on some of their prized trees and shrubs. This is the time of year when the winter damage known as “winterburn” is most evident on evergreens.

Winterburn, which is also known as sunburn and windburn, is a common winter injury of northern evergreens, especially those that are marginally hardy or are being grown in inappropriate locations in the landscape. Gardeners can identify winterburn by looking for golden or brown needles on their pines, junipers, yews and spruces, almost always above the snow line. Sometimes, entire branches are dead, and a truly severe case of winterburn can completely kill an evergreen, rendering it brown and crispy, as though it had been baked in an oven! This winter damage to evergreens is caused by a combination of winter sun and persistent cold, drying winds, which both draw upon the reserves of moisture in the needles. If the ground is still frozen and the plant cannot replenish this lost moisture, the result is death of the green tissues, and loss of the needles.

Winterburn doesn’t occur on the coldest days of winter, but rather in early spring, when the sun is already high in the sky, but the ground is still frozen. It tends to be most severe in years when snow lingers into March and April, reflecting the light of the sun up into the branches. The problem is made much worse when evergreens are planted along the south or west side of a white house, which reflects the sunlight onto the back of these plants, burning them from both sides.

There are a number of ways to prevent winterburn damage to evergreens. First, be sure to choose evergreens that are resistant to windburn and are adequately hardy for your area. Secondly, never plant evergreens right along side the south or west wall of a white house, unless you are in a really warm part of the North. Thirdly, plant tender evergreens in a location with some protection from winter winds. Finally, be sure to give your evergreens a good watering just before freeze-up in fall, to boost their moisture reserves. Other than these practices, a protective burlap shield supported on the south and west side of the evergreen by wooden or metal posts will block both the sun and the wind, and increase the plant’s chances of successfully making it through the early spring.