As ice and snow treated with rock salt melts, the resulting runoff and airborne spray may injure vegetation – particularly evergreens. Here’s what to look for:
- When road salt is sent into the air by vehicles, tree damage is usually most severe on the lower part of the tree, facing the street. Damaged trees also tend to have thinner crowns and initiate growth later in the spring.
- Wilting and scorching of leaves and other foliage are often present, though symptoms are usually evident only after large masses of salt have accumulated.
- Damage from salt in the soil can be spotted by noticing significant wilting, especially at the top of a tree, where salt inhibits absorption of water by the root system.
- Other symptoms include: stunted foliage; browning of foliage; thinning of branch tips; premature fall coloration and defoliation; and dead branches.
Damage from deicing salts is hard to prevent. Start by planting trees tolerant to salt (such as birch, oak, or juniper) near the road and driveway. Beyond that, monitor plants to ensure their overall health, keep trees well watered and use gypsum (calcium sulfate) to help counteract salt in the root system. Other preventative measures include diverting salt sources from trees by erecting barriers of burlap or wood; laying down mulch to prevent seepage; and watering during dry periods especially in spring when the ground thaws.