Here in the Midwest, it feels like we’ve been stuck in the polar vortex all winter. Ice melt has been in high demand — the big box home improvement store near our house said they sold nearly 5,000 bags of the stuff over the weekend. Ice melt has the immediate effect of making concrete driveways and pathways less slippery, but it also has long-term effects on nearby plants. Here are a few tips on how to recognize the signs of ice melt damage to trees and shrubs, as well as how to mitigate the effects of these chemicals.
Many ice melt products contain sodium chloride (rock salt) and ammonium nitrate. Both of these chemicals can harm trees and shrubs. Large amounts can even kill plants. Evergreens are quick to show damage from ice melt. You may notice that the lower needles are turning. The damage will be most evident on the side facing the exposure.
Deciduous trees may not show any evidence until the following growing season, but then yellowed or dwarfed foliage may become apparent. Branches and leaves often die back. These chemicals can stunt future growth and make your landscape plants more susceptible to disease.
Once you notice the damage, it’s best to just prune away the affected branches. You may also apply gypsum to the soil to neutralize the chemicals. Gypsum is a naturally-occuring mineral that doesn’t harm the environment — you can even apply it as a preventative measure. Horticultural gypsum is available from lawn and garden centers.
If you’re buying ice melt for your own property, look for calcium chloride instead of sodium choloride — it causes less damage. Try to remove ice through mechanical means if possible. Avoid applying ice melt chemicals in late winter or early spring as plants are exiting dormancy, because they are the most vulnerable at this time. Rinse off any visible salt residue from your trees and shrubs.
Here’s hoping that winter is on its way out — I can’t wait for spring!