Avoiding Winter Burn on Evergreens

If you checked out our last two blog posts, where we discussed preventing sunscald, then you know that just because the snow starts flying it doesn’t mean you can take a break from yard work for a few months! Like sunscald on thin-barked trees, winter burn is a problem that affects evergreen trees and shrubs during the harsh winter months.

Have you ever noticed brown or rusty colored patches on your evergreens? If so, then you’ve witnessed the damaging effects of winter burn, first hand. Winter burn occurs when evergreens become dehydrated during the natural process of transpiration. When evergreens start to photosynthesize on warm, sunny days, they release water as part of the process. This, in addition to insufficient watering prior to winter and heavy wind over the course of winter, can cause the dehydration that leads to brown, dead needles.

The best way to prevent winter burn is to avoid it all together! Choose evergreens that are suited for your region (find your zone), with a reputation for being able to withstand winter burn, and avoid planting them in windy areas. Evergreens that are less prone to winter damage include: Sitka Spruce, Holly, Colorado Blue Spruce, Taunton Yew, and Techny Arborvitae. Varieties that tend to be most susceptible are broadleaf evergreens, like Rhododendron and Laurel, and other varieties like Dwarf Alberta Spruce, Juniper, Pine, Hemlock, and new plantings.

If your evergreens are already in the ground, and they’re not going anywhere, there are several ways to keep them safe during winter. In the fall, make sure your evergreens are being watered the equivalent of one inch of rain per week; keep watering during the winter until freeze up, to increase moisture uptake. By covering the roots of your evergreens with several inches of leaf or bark mulch, you’ll preserve the moisture you’ve so diligently provided.

Keeping your weak, susceptible, or newly planted evergreens wrapped in burlap (available at garden centers) will block the sun and glare from snow, and prevent the plant from photosynthesizing and losing moisture. Just make sure to wrap it loosely with twine, leaving the top open for air to circulate.

If you already have winter burn damage, wait until new growth has begun before removing dead stems. Nurture your evergreens with fertilizer and a light application of mulch around the roots, to hold in moisture. And if one of your evergreens didn’t make it, be sure to remove them before they become hosts to insects and disease.

By following these methods, you should be on your way to keeping the green in evergreen!