University of Illinois Extension
Bruce Spangeberg

These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area.

Stateline Yard & Garden

Deicing Salts Can Damage Plantings

December 17, 1998

Despite a mild start, this winter most likely will include snow and ice at some point. Deicing salts will be used to help assure safety on sidewalks, driveways, and parking areas. Keep in mind, however, these salts can also cause damage to plantings in the area, so use some caution with them this winter.

In residential areas, trees, shrubs, lawns, and other landscape plantings can be damaged by deicing salts accumulating in the soil, either deposited directly from plowing or through runoff as snow melts in spring. Diagnosing salt damage can be difficult. General decline of plants can be due to a variety of factors. If declining plants are located near sidewalks, roadways, or parking lots, consider deicing salts as a potential source.

Plants take up chloride from salts accumulating in the soil. This can lead to dieback and decline. In addition, sodium from salts may destroy soil structure, causing more plant problems. Most damage will occur within 30 feet of the roadway or parking lot.

Salt damage depends on a variety of factors, including type and amount of salt, timing of application and species of plants. Sodium chloride, although cheaper, is more damaging to plants than sources such as calcium chloride. Only apply the amount of salt needed to do the job. Mix salt with sand (for traction). Try to shovel or plow before salting. Also, consider where snowmelt goes and vegetation that may be affected when deciding where to pile snow.

Applying gypsum to lawns is sometimes suggested to counteract the salt, but good soil drainage is needed. Typical turf areas near roads, sidewalks, and parking lots usually have poor soil drainage, limiting the effectiveness of the gypsum.

Along highways, trees are often damaged by salt spray from high-speed traffic. Evergreens will show browning of foliage. Deciduous trees often show a clumping of twigs called witches brooms, due to buds being killed by salts settling on the branches. Temporary screening may help prevent damage. Also be aware of areas prone to salt spray when choosing plant material for these sites so salt-sensitive species are not used.



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