How to deice and be nice to your plants
by Jo Ellen Meyers Sharp
Winter is upon us and there are a few steps we Midwesterners need to take to protect our plants, pets and landscapes from the elements. Icy sidewalks and driveways are hazardous to people and pets, so it's important to keep them cleared. But some of the deicers on the market are hazardous to plants.
"Avoid using any salt-based products," says Sarah Newcam, supervisor at highly rated Natorp's Garden Store in Florence, Ky. "Salts will adversely affect plants or kill them."
Damaged perennials, shrubs and trees will have branches that look burned next spring when they leaf out. Grass will be brown. In general, deicers are made from five chemicals, including chlorides, which are salt-like products that may cause concrete to crack or discolor. These also may be harmful to pets because the salts accumulate on paws that get licked.
The best way to prevent ice buildup is to shovel the snow. Be careful not to dump snow or ice that has been treated with deicers on plants. Non-clumping kitty litter, sawdust, coffee grounds or sand also can be used to increase traction on ice and help melt it, albeit slowly. Be careful about tracking these products indoors.
Road spray can be particularly deadly to plants because of the heavy concentrations of deicer chemicals crews apply. And, in some Midwest regions, snow and slush are mounded deep for weeks, which can smother, freeze or drown roadside plants.
"Broadleaf evergreens, such as rhododendrons and azaleas, may need extra protection," says Dottie Wright, manager at Dammann's Lawn Garden & Landscaping Center in Indianapolis. "Anti-desiccants are wax-based products, which coat leaves and protect them from moisture loss. Broadleaf evergreens benefit from anti-desiccant sprays such as Wilt-Pruf. Just be sure not to spray the underside of leaves," she says.
If the branches of evergreen shrubs bend under the weight of snow, gently brush it off with a broom or your hand. It's best to let Mother Nature melt the ice from branches. Trying to knock off the ice can break or damage branches.
"To protect weaker-branched evergreens, tie them up with twine," says Rudy Zeilhofer, general manager of Stein Garden & Gifts, located throughout Wisconsin. "Starting at the bottom, wrap the twine round the shrub so that the branches are pulled to the center of the plant."
Whichever deicer you select, always read and follow the label directions. Here are some common chemicals found in deicers and their potentials pitfalls for your landscape:
- Calcium chloride, when used properly, will not likely harm plants.
- Salts can change the chemical balance of the soil and can accumulate to toxic levels.
- Potassium chloride is a saltlike product, which may injure plants and the roots of plants.
- Urea is a fertilizer, however it can contaminate the soil and surface water runoff with nitrates.
- Calcium magnesium acetate isn't considered hazardous to plants. Unlike other materials, it doesn't form a brine. Instead, it prevents snow particles from sticking to each other on surfaces.
Sometimes known as the Hoosier Gardener, Jo Ellen Meyers Sharp lives in Indianapolis, where she manages perennials and woody plants for a large, independent garden center. A freelance writer, her work appears in many publications, including The American Gardener and Garden Gate. Sharp also speaks about gardening throughout the Midwest and is a director of the Garden Writers Association.