Salt Damage to Plants
Every winter, the Ohio Department of Transportation, city, county and township personnel spread hundreds of thousands of tons of salt on Ohio streets and roads. And, with the very robust winter, homeowners also have spread large amount of salt to melt ice and snow. When salt is splashed onto evergreen foliage by vehicles, or the wind, it can cause browning, die-back or be growth stunting. In extreme cases, plants may die of salt exposure.
Wind-driven salt spray can affect plants a significant distance from highways, perhaps up to 100 - 150 feet depending on the force and direction of the wind. Symptoms of airborne salt injury to evergreen plants such as pine, spruce and fir typically appear in the side of plants facing the salted area. However, in some years when large amounts of salt are used and winds are favorable for drift, the entire plant can be injured. Salt damage on evergreens will begin to appear now and progress into the growing season as needles turn progressively brown often from tip to base. Damage to deciduous plant - those plants that drop leaves in the fall - will not be noticed until spring when plants may not leaf out or flower normally due to injury to buds. Chloride from salt spray damages plants by accumulating to toxic levels in needles and/or buds.
Salt also can damage plants by accumulating to toxic levels in the soil surrounding plants. When this occurs, plants are unable to take up adequate water and may appear as if drought stressed in addition the toxicity of the chloride. Where salt was applied to sidewalks and driveways, a high level of salt in the soil is probably the most common threat to landscape plants that homeowners may encounter where salt was applied to sidewalks and driveways. If snowmelt and/or rain doesn’t move or dilute the salt, new leaves and growth may be damaged . In severe cases, a plant may be killed by excess salt in the surrounding soil. To help prevent salt damage to plants: Grade walks so they drain away from plantings. Rinse plants sprayed by salt with water, when weather conditions warm; but do not saturate soils in winter. Consider using sand, gravel, kitty litter or cinder instead of salt around sensitive plants such as Japanese maple, rhodendron and azalea to provide traction on ice. Attempt not to pile ice or snow where significant amounts of salt had been applied around trees or shrubs or in places where melt will drain onto trees or shrub roots. Finally, if you suspect excess salt in your soil, flush areas near tree and plant roots with water as soon as soils will drain (after ground thaws).