AMES, Iowa — Horticulture specialists with Iowa State University share information about how snow can either benefit or damage landscape plants. To have additional questions answered, contact Hortline at hortline@iastate.edu or 515-294-3108.
Is snow beneficial to landscape plants?
A layer of snow is beneficial to many plants in the garden and landscape. A layer of snow protects plants from extreme cold and the drying effects from sun and wind. A layer of snow also prevents repeated freezing and thawing of the soil, which can heave perennials, such as garden mums (Chrysanthemum spp.), Shasta daisies (Leucanthemum spp.), painted daisies (Tanacetum spp.), and coral bells (Heuchera spp.), out of the ground, causing serious damage or death. Additionally, a layer of snow moderates soil temperatures. Without snow, the soil can get extremely cold, damaging the roots of trees, shrubs, and perennials.
On the negative side, the weight of heavy, wet snow can break the branches on trees and shrubs and destroy the shape of multi-stemmed arborvitae and junipers. A deep layer of snow also deprives rabbits and deer of food on the ground, forcing them to browse on trees and shrubs that stick above the snow. Heavily browsed trees and shrubs can be destroyed.
How can I prevent heavy, wet snow from damaging small trees and shrubs in the landscape?
The weight of heavy, wet snow can cause considerable damage to small trees and shrubs. When heavy, wet snow accumulates on small trees and shrubs, gently shake the snow from their branches or carefully brush off the snow with a broom. When clearing driveways and sidewalks, don’t throw or push heavy, wet snow onto small trees or shrubs. Also, avoid dumping snow onto small trees and shrubs when raking snow from rooftops.
To prevent the weight of heavy, wet snow from damaging arborvitae and other multi-stemmed evergreens, wrap the plants with twine or rope in fall.
Do I need to uncover small evergreens if they are buried in snow?
There is no need to uncover evergreens buried in snow. The snow will not suffocate the evergreens. Snow acts like an insulating blanket and protects the evergreens from desiccating winter winds.
— Richard Jauron and Laura Sternweis, Iowa State University Extension and Outreach
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