Across the Midwest, the use of deicing salts in winter to maintain safe roadways, sidewalks, and driveways is a common practice. Despite the benefits, deicing salt deposited on trees and shrubs can cause extensive damage. Deicing salt is dispersed from roads by plowing, meltwater runoff, splash, and aerial spray. Plants sensitive to salts may show injury early and can decline quickly after exposure.
Damage is most severe within 60 feet of the road and decreases with distance, but sensitive plants can show burn at distances of 1,000 feet or more from roadways On evergreens, salt spray causes browning or yellowing of needles and twig dieback, often on the roadside portion of the plant only; sensitive evergreens planted within 300 feet of roadways can sustain severe damage.
To minimize injury, keep plants healthy by mulching to reduce water loss, and by irrigating to help move salts through the soil. Also, wait to apply a deicer until after shoveling and plowing. Avoid shoveling salt-laden snow over the root zones of salt sensitive plants. Avoid or minimize the use of salt around landscape plants.
Source: For more info, check out The Morton Arboretum’s full Salt Tolerant Plant Guide.