I have also noticed significant winter burn on my boxwood and on other broadleaf evergreen plants around the Miami Valley.
Holly, boxwood, rhododendron, azalea, euonymus and southern magnolia are the most common broadleaved evergreens we have in this area. Since they retain their leaves during the winter months, they are susceptible to winter burn.
The damage looks just like it sounds — like the foliage has been scorched or burned. It is generally a light straw color and typically occurs on the side of the plant that is exposed to the wind.
My boxwoods are in the front of my house facing south and in a perfect environment for winter burn.
Broadleaved evergreens store their sugars and energy in the leaves of the plant. In addition, since these leaves are present during the winter, they tend to need a little water to sustain them.
This past winter, the soils were frozen most of the time and the winds were prevalent. This is a perfect combination for winter burn.
Winter burn is caused by desiccation of the leaf tissue. As mentioned above, they retain their leaves during the winter and there is some transpiration or water loss. It’s typically low during winter months but increases with drying winds or sunny locations.
As I mentioned, my boxwoods are on the south side of the house so when the sun was out, the heat reflection off the brick kept them a little warmer than if they were on the protected north side.
Water is lost through transpiration in the leaves and can’t be replaced if the soil is frozen or dry. Thus, the winter burn symptoms show up in the late winter or early spring.
In most cases, these plants survive. They will send out new shoots and growth once spring weather hits. The new growth sometimes pushes off the dead or dried up leaves.
The best thing to do is check for damage. If you notice branch damage, you can prune this off before new growth occurs. If you aren’t sure, wait until the plant starts to send out new growth and see what happens. This is what I plan to do.
Winter burn can be prevented with a protective spray of anti-dessicant in the fall prior to the ground freezing.
I have also noticed dwarf Alberta spruce with winter burn as well. Again, the damage is on the dominant wind side. Wait to see what branches out and prune out any dead. The plant may look a little bare until the new growth fills in; this may take a little time since it’s a slow-grower.
About the Author