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Knowledge to Grow by Gail Daniels - Garden Blanket


Though you may not agree after this long cold snowy winter, snow is actually good for your garden and landscape. Perennials, trees, shrubs and lawns love and need snow for protection. Snow is an excellent insulator for plants from low temperatures and blasts of arctic air.

Snow brings welcome moisture to many landscape plants. Dormant plants loose moisture from twigs as water vapor in a process known as transpiration. Evergreen plants that keep their leaves are at even greater risk of injury.

The deeper the snow is, the greater the insulation. Temperatures below the snow increase about 2 degrees F for each inch of accumulation. In addition, the soil gives off some heat. Fresh, uncompacted snow has 90 to 95 percent air trapped between its crystals. Because the air can barely move, it can’t easily transfer heat away from the soil or the cold down into the soil.

Some evergreens can suffer from too much snow load. The weight of snow and ice can bend or even break branches, especially on multi-stemmed shrubs such as arborvitae. You can gently brush away the snow with a broom. Do not try to remove ice because it is more likely that you will break the stems. Multi-stemmed shrubs that are particularly susceptible to breakage can be bound with twine to hold the branches together.

Your plants are actually better off having a winter where you have snow and the temps stay in the 20 degrees F range than a winter where the temps fluctuate above and below the freezing point provided the climate such as ours is supposed to have a cold winter. Snow does one little tiny thing that keeps it from being a really great insulator. It melts. Not only is the above ground temperature hard on the plants, but the thawing and “heaving” of the ground can expose roots and severely damage or kill the plant. This year, so far, it should not be a problem with alternating freezing and thawing ground temperatures!

Snow also lets us look at our flower gardens in a special way. Snow covers everything and yet it makes so many things clear. It pops out edges and shapes, teaches lessons about garden structure and helps us plan a better summer landscape. Focus on hardscapes and plant forms. Maybe in a far corner a dwarf tree or shrub would be perfect; or maybe a trellis or arbor.

Thinking of snow as white highlighter lets you see the basic form and structure of your garden. I have read that if a garden looks good in winter, it will look good in summer because stripping away flowers and foliage shows off balance and form, the way snow show off the lines of buildings.

So, here’s to snow!! And to Spring which is only about seven weeks away!



The Purdue University Cooperative Extension Service can be reached at (260) 499-6334 in LaGrange County.