Everything You Need to Know About Winter Desiccation

One of the most common winter related tree issues in Maine is winter desiccation (also called winter drying). Winter desiccation occurs when the foliage is exposed to high winds and low temperatures, but since the ground is frozen, the tree is unable to replace the moisture lost from the foliage. This tree injury is common in Maine, particularly in trees with shallow roots or in low, wet sites. Many trees will fully recover once new foliage develops in the spring.

Typically, winter desiccation affects trees like the Norway Maple, Juniper, Birch, Silver Maple, Linden, Colorado Blue Spruce, Norway Spruce, and other evergreens. The main sign of winter desiccation is discoloration of evergreen needles, making them a reddish-brown color.

How to Prevent Winter Desiccation

Prevention measures must be practiced all year to protect plants during the winter. Proper watering is the most direct way to prevent winter desiccation, since it is a result of over drying. Year-round watering helps keep your plants healthy and ready for winter weather. Give plants a deep soaking before the ground freezes if it has been a dry fall season. This gives them more moisture before the frozen ground prevents the roots from getting enough water.

Another preventative measure is mulching. A two-inch layer of mulch around your trees will reduce water loss and protect the trees’ roots. Small evergreens can also be supported with windbreaks to protect against the wind.

What to Do After Winter Desiccation Occurs

Despite preventative measures, winter desiccation is hard to avoid completely, especially
if you have many trees susceptible to the injury. Wait until new growth has developed before pruning. Once new growth has started, prune dead branches and branch tips to avoid making your tree attractive to pests that eat dead tree materials.

Keeping trees watered throughout the summer, fall, and leading up to winter can help prevent winter desiccation. After winter, pruning can help restore trees’ aesthetic appeal and protect against pests and fungi.