As spring unfolds, winter injury to landscape plants rears its ugly head. One common type of damage is the dreaded winter burn. Winter burn shows up as red, brown, yellow, or bleached looking foliage on many common evergreens. Boxwood and arborvitae are especially prone but spruce, pine, and others are also vulnerable. Note that some evergreens like certain junipers take on a naturally orange, purple, or brown cast over winter, so some discoloration in your landscape might not be worrisome at all.
What Causes Winter Burn
Drying winter winds and harsh sun are major contributors to winter burn. Plants in exposed areas will be particularly affected and especially on the south, southwest, and west sides. Wind and sun desiccate the needles and since the root zone is frozen, the plant is unable to take up water to replace what it has lost. The result is the signature dried out burned looking foliage, often concentrated on just one side of the tree or shrub.
Plants in dry sites and drought conditions, recently planted evergreen trees and shrubs, and those that were planted very late in the season are more vulnerable to winter burn. Plants with less established roots and those that haven’t had regular access to moisture struggle to keep up with the water loss that occurs over a long winter.
Trees that prefer protected areas (Canadian Hemlock, for example) will struggle if they are exposed to harsh winter conditions, so be sure to follow the “right plant, right place” mantra. Likewise, salt from roadways and sidewalks can also contribute to winter burn, so be mindful in site selection and avoid planting evergreens near heavily salted areas.
What to do About Winter Burn?
The good news is that plants usually make a good recovery from winter burn, so if you see it in your landscape, don’t panic and don’t remove the plants just yet. You will likely see healthy new growth start as the weather warms and that new growth will eventually fill in and mask bare spots. Plants like arborvitae and boxwood that are a bit more prone to winterburn can be pruned to improve their appearance. Just prune out the damaged foliage with a clean tool after new growth begins in spring.
Plants like spruce and pine will often naturally hide the burned foliage as they put on new growth at the ends of their branches, so intervention may not be required. If entire branches fail to begin growing, you may prune them out if desired.
To avoid winter burn in the future:
-Aim to plant evergreens by late summer or very early fall to give them a chance to establish.
-Right plant, right place. Consider wind, sun, and salt exposure.
-Regular watering up until the soil freezes is essential for new plants. Older, more established evergreens will also appreciate a few deep waterings at the end of the season, especially after dry summers.
-A layer of mulch, compost, or leaves helps conserve moisture and protect plants.
-Set up a snow fence, burlap wrap, or some sort of wind barrier for plants that are in exposed sites, especially if you are planting late in the season.
It’s important to remember that while deciduous plants drop their leaves to conserve moisture, evergreens continue to lose water all winter and they will fare better with more reserves. By following a few guidelines, you can ensure that these otherwise resilient plants look their best after a long winter.