When we think about damage to plants in the winter, most of the time we think of branches breaking due to snow or ice. However, winter burn can be a big problem with evergreens. Evergreens do not shed their foliage like deciduous trees do, making them more vulnerable to damage. Winter burn happens when the tips of evergreen trees and shrubs and new shoots dry out due to exposure to winter conditions including sun, drought, and extreme cold.
Factors That Lead To Winter Burn
Sudden changes in temperature and exposure can cause winter burn damage. Rapid onset of freezing temperatures after warm fall temperatures can damage foliage. Trees with shallow root systems that lack efficient water uptake are the ones who suffer the most. Transpiration, or water uptake, is slowed because of the frozen ground. When the trees lose water they are not replenished by the roots so the foliage dries and dies. Rapid cooling after the sun goes down can also be enough to trigger ruptures in plant cell walls and cause browning and dieback of plant tissue. Use of de-icing salts that come in contact with foliage or saturate the soil around a tree can also cause winter burn.
How To Protect Plants from Winter Burn
There are steps you can take to protect your plants:
Plant evergreens on the shaded sides of houses. Snow-covered or shaded foliage is not usually affected because it experiences less evaporation caused by the sun.
Choose evergreen species that are appropriate for the cold hardiness zone where you live, and well-suited to soil conditions.
Time planting of evergreens in the spring before bud break or late summer to allow time for root acclimation and growth.
Mulch around the base of plants to retain water and shield roots from cold weather.
Put up a burlap barrier to stop wind from drying foliage out.
Reduce use of de-icing salts, especially where the meltwater could reach the soil near the evergreen.
Treating Winter Burn in the Spring
Damaged branches can be pruned off if they are dead. If they are alive after bud break or show signs of green in buds then they may recover, so they should be left on.
Use of a growth regulator can also extend the life of evergreens affected by winter burn. The foliar application slows growth by 35% to 50%, allowing the evergreen to reallocate resources to new growth to fill in damaged spots. Hoppe’s plant health care technicians perform growth regulator treatments for winter burn in the spring and in the fall.
Soil injection fertilization can also help in the spring by bringing this growth back to life for the season, and in the fall by building up the evergreen’s resiliency going into the winter months.
If you believe winter burn has damaged your evergreens, or you’d like an opinion by a certified arborist, contact Hoppe today at 414.257.2111 to schedule an inspection. We perform professional diagnosis on plant health care issues, including winter burn, and can recommend a plan for treatment and prevention.