Heavy snow and ice on the branches of trees and shrubs can cause considerable damage. Multi-stemmed evergreens, such as junipers and arborvitae, and weak-wooded deciduous trees, such as Siberian elm and silver maple, are most susceptible to branch breakage. Improper removal of ice and snow can increase the amount of damage to trees and shrubs.
Managing Ice | Managing Heavy Snow | Addressing the Damage from Ice and Snow | More Information
Managing Ice
During the winter months, the most serious damage to trees and shrubs generally occurs during ice storms. Large branches or entire trees can be lost due to the tremendous weight of the ice. When the weight of ice causes a small tree to bend sharply, it may be possible to prop it up to prevent breakage. Don't push ice-covered branches back upright; simply support them to prevent further bending. Don't attempt to remove the ice by beating the branches with a broom or rake. This will only cause greater damage.
If the temperature is above freezing, spraying the ice-coated branches with cold water will help melt the ice. Do this with caution, as the cold water may also add weight to the tree, causing further breakage. Hot or boiling water, however, may actually injure the trees and shrubs. In most cases, it's best to let the ice melt naturally. The radiant heat from the sun on a warm winter day can melt ice relatively quickly.
Individuals should stay away from large, ice-laden trees. Nothing can be done to prevent damage to large trees. Individuals, however, can be severely injured or killed if a large tree or branch were to suddenly crash to the ground while underneath it.
Managing Heavy Snow
Accumulations of heavy, wet snow on evergreens can also cause severe branch breakage. Damage from heavy snow is best managed with prevention. Tie up vulnerable plants (such as arborvitae) before a snow or ice storm to help support branches and create a cone shape that will shed snow more easily. Use sturdy strips of fabric, nylon hose, or flexible cords (like bungee cords) instead of materials that could cut into the bark and cause additional damage. Remove these protective materials after the risk of heavy snowfalls passes for the season - typically mid to late April across much of Iowa.
When heavy, wet snow accumulates on evergreens, gently shake the snow from the branches or carefully brush off the snow with a broom by sweeping upward. Never brush downward – you risk breaking already bent and stressed branches.
Snow can slide from steep roofs onto plants. Construct a temporary wooden structure in the fall to protect the plants.
Don't throw heavy, wet snow or ice onto shrubs or small trees when shoveling driveways and sidewalks. The weight of the heavy, wet snow and ice can cause considerable damage.
Addressing Ice and Snow Damage
If branch breakage occurs on a tree, prune back the damaged limb to the main branch or trunk in late winter when you can access the branch safely. Damaged shrubs may need to be pruned in the spring to restore their attractive, natural shape.
Sometimes, trees and shrubs maintain a drooping, bent, or distorted form even after the snow and ice melts. Be patient with these misshapen trees and shrubs. Branches are remarkably flexible. As long as they are not broken, branches will move back into their original position. This may take several weeks or even months, depending on the weather. Resist the urge to “help” out by propping or tying up branches. You risk breaking branches in the process.
Occasionally, bent branches do not return to their original position. If branches remain bent or distorted into early summer, a few options exist to improve appearance. Some plants may be so disfigured that it is better to remove and replant. In many cases, the branches can be trained back into position. Use broad flexible straps to reposition branches to their desired form utilizing bamboo stakes or other items to brace them. Be sure that any ties or straps used for training are not left in place for more than two growing seasons. These materials will eventually girdle branches and kill them if forgotten or left on the plant.