We are already noticing “browning needles” on a variety of trees and shrubs including Conifers, Pine Trees, and Evergreens. We also see browning on leafy plants like Euonymous, Boxwood, and other trees and shrubs which keep their leaves all winter long. It was unusual to start seeing this damage while we were still in the grasp of winter, but, due to this year’s unusually cold polar vortices, we were seeing continued damage in many locations.
What Causes Winter Burn?
Winter Burn results when air temperatures rise for short periods of time over the winter and plants begin creating food and energy from within, through the process of photosynthesis. In doing so they release large amounts of water through their leaves and/or needles as they warm, but since the ground and roots remain frozen, and roots cannot absorb water when frozen, the plant cannot replenish the lost moisture which results in browning.
It is important to remember, every fall, to make sure to thoroughly water your trees and shrubs just prior to ground freeze unless we have had ample rainfall. Having trees and shrubs fully loaded with water going into the winter greatly reduces or eliminates Winter Burn.
What Can You Do About It?
If you notice browning on any of your trees or shrubs, what can you do now? Water thoroughly, as soon as the ground thaws. Many home owners mistakenly think that melting snow adds substantial soil moisture in springtime, helping their trees and shrubs.
This is unfortunately not true. Why? Obviously the ground is frozen all winter long so melting snow runs off into the sewers, rivers and lakes before the ground can thaw enough for much absorption to take place. Therefore, as soon as the ground does thaw, if we do not receive normal amounts of spring rain soon thereafter, water your plants at that time. Doing so will limit some of the Winter Burn damage that has yet to appear.
When Should You Water?
How can you tell if the ground is ready to absorb water? Step a shovel into the ground. If it easily penetrates at least 6 to 8 inches, it’s time to water.
Will Winter Burn Kill Plants?
In some instances, yes. But don’t be hasty in removing plants. Wait to see if new growth emerges this spring and into the summer. If new growth does emerge, much of the damaged foliage will fall from the plant over the summer and the new growth will fill out and rejuvenate the plant over time.
Proper watering, in combination with high quality root fertilization, will go a long way in helping your trees and shrubs to recover.