Christian County Extension Office
Consider Plants When Using Deicing Salt
Deicing salts are helpful in providing dry, safe pavement for walking and driving. They are used in large quantities to improve safety during icy conditions. While deicing salts are important tools, the runoff from treated pavement contains dissolved salts that can injure and even lead to decline and death of many trees and other vegetation.
Most damage occurs within 30 feet of a roadway or parking lot. Along high-speed roads, salt may also drift onto vegetation, up to 60 feet or more away. Salt spray commonly causes bud death and twig dieback in deciduous plants. This may result in a type of ‘witches’-broom’, tuft-like growths from branches facing the road. Evergreens may exhibit moderate to extreme needle browning, beginning with the tips of needles and twigs facing the road. This becomes evident in late February or early March and intensifies through spring and summer. Other symptoms of salt injury include stunted leaves, heavy seed load, twig and branch dieback, leaf scorch, and premature leaf drop.
In residential areas, trees, shrubs, and lawns are more often damaged by salts accumulating in the soil. Soil salt damage often becomes evident late in the summer during periods of hot, dry weather. Symptoms may include abnormal foliage color, needle tip burn, marginal leaf burn, reduction in flower or fruit size, stunting, premature fall color and a general decline in health. Unfortunately diagnosing salt injury can be difficult as symptoms are similar to injury caused by other stresses. Soil and tissue analysis can verify salt injury.
There a few options for minimizing salt damage on paved surfaces around your home. Following some of these tips can help reduce injury to your plants while still reducing slippery surfaces.
- Limit applications to high-risk locations (i.e., steps, walkways). Reduce the quantity applied by mixing the salt with abrasives such as sand or kitty litter. Deicing salts such as calcium chloride and calcium magnesium acetate are less damaging than sodium chloride.
- Plants along the street are especially susceptible. Consider constructing a physical barrier made of plastic, burlap, or snow fencing and place the barrier between the pavement and the plants when salt trucks are likely to be active.
- Avoid planting trees and shrubs in spray drift zones or where salt-laden snow will be deposited.
- Maintain a healthy soil and healthy plants. Provide irrigation and mulch to reduce water loss. Prune, fertilize, and treat for problems correctly.
- Select plants that are more tolerant to salt injury. No plant is completely tolerant and there are only a limited few that can survive under higher salt levels. White Oak, Ginkgo, Japanese Tree Lilac, and Eastern Red Cedar are a few examples.
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UNIVERSITY OF KENTUCKY, KENTUCKY STATE UNIVERSITY, U.S. DEPARTMENT OF AGRICULTURE, AND KENTUCKY COUNTIES, COOPERATING