Along with the Christmas decorations, local stores are stocked ceiling-high with bags of rock salt, the traditional fix for icy sidewalks and driveways. Rock salt does a good job of de-icing, but it can seriously injure or kill plants growing nearby.
The most obvious damage occurs to turfgrass. The salt kills the grass leaves, crowns and roots. The turfgrass kill is very apparent along the road on which I live. The town spreads salt on the gentle hill in front of my house and each spring there is an even foot-wide swath of dead grass along both edges of the road. Weeds that tolerate the high salt levels take the opportunity to rush right in to replace the dead grass.
Trees and shrubs are also damaged by salt. When the ground thaws in spring, the salt leaches into the soil and damages the plants’ root systems causing leaf scorch and stunted growth the following year. Sugar maples in particular are very sensitive to high salt levels in soil. They will decline over a period of years and then die prematurely.
Salt spray from traffic can accumulate on evergreens and cause the needles to turn brown and fall off. The plant usually survives because the side away from traffic stays healthy, but the side toward traffic will have only the current season’s needles the flowing summer and will look rather ragged. The solution to this, while not aesthetically pleasing, is to place a barrier between the road and the evergreens for the winter. I’ve seen plastic tarps, plastic orange snow fences and burlap stapled onto wooden stakes to form barriers.
There are alternatives to using salt to melt ice on your own property. Organic Gardening magazine says that the most environmentally friendly product you can use on slippery sidewalks is alfalfa meal. The nitrogen in the meal promotes melting while the granular texture provides traction. After it has done its job, the used meal can be swept onto the lawn or flowerbeds to naturally amend the soil. Any nitrogen in the meltwater will give the plants a gentle boost in the spring. Alfalfa meal can be purchased at feed mills for about $15 for a 50-lb bag.
Kitty litter mixed with sand will not melt the ice, but it will provide traction until the weather gets warm enough for the ice to melt. When the area dries completely, you can sweep up the sand mixture and use it again.
Avoid products labeled landscape-friendly ice melters if the active ingredient is a synthetic urea fertilizer. It is not as caustic as salt but it can burn plants and leach into groundwater.
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