University of Vermont Extension
Department of Plant and Soil Science

Winter News Article


Contact: Dr. Leonard Perry, Extension Professor
University of Vermont

This is the time of the year I find many home gardeners begin to have concerns about the damage snow may do to shrubs and trees. While it's true that heavy, wet snows and ice often cause broken branches, snow itself will not hurt landscape plants. In fact, the opposite is true. Snow is a very good insulator against chilling temperatures that may injure plants.

Snow on the ground prevents injury to roots, which generally can't withstand extreme cold. The roots of most landscape plants will be injured at soil temperatures below ten degrees F with more sensitive perennials injured at soil temperatures just below freezing. Snow acts as an insulator or blanket, as do mulches, and is one of the best mulches for winter protection.

But snow can cause damage, especially when deposited on plants by snow blowers and snowplows. Snow pushed or thrown over plants is denser than natural snowfall and tends to stick together. As it settles, it can rip branches from shrubbery.

Branches that normally bend will break in winter when they are frozen and brittle. This was seen by those in northern New England in the January 1998 ice storm. If snow is dumped on plants, it may be better to leave it than to try to remove it to prevent further breakage of the branches.

Of course, the best solution is not to cover plants with excessive snow. Foundation plantings are often more vulnerable to mechanical injury from snow or ice.

Snow or ice sliding off the roof may crush the plants below. One year such a snowslide even dented the heavy metal lid of my bulkhead!  If plants are already covered with deep, natural snow, this may cushion the impact of falling ice and protect the plants. If little snow is present, you can protect plants by placing teepee-shaped wooden frames over them.

If you are concerned about injury to your favorite plants from the settling snow, protect them by scooping the snow away from the plant. Then, with gloved hands, carefully remove the snow from the branches. Natural snowfall or windblown snow seldom result in plant injury. It's usually the devices we use to remove snow that cause the most damage.

This winter, be careful when shoveling, plowing, or blowing snow. If you can't remember where plantings are located, place posts with reflectors next to the plants.

If you are using salt on walks and drives, keep in mind that this, mixed with the snow and slush that is piled around plants, can leach into the soil and harm roots. Avoid piling salty snow near plants or on lawns. If this is not possible, use one of the environmentally safe salts such as calcium chloride or an ordinary, inexpensive garden fertilizer, sand, or kitty litter mixed with equal parts of "safe" salt.

This winter, play it safe. By using the right materials on walks and drives and extra care when removing snow, you can keep your trees and shrubs safe from snow injury. 

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