SPRINGFIELD, Mo. — During the winter, people rush to the car wash to rid their vehicle of accumulating salts. Just as salts cause vehicles to corrode, it can also create problems for landscape plants, according to Patrick Byers, a horticulture specialist with University of Missouri Extension.
Winter storms result in tons of salt added to the roads and sidewalks each year. When snow is cleared, it often ends up being sprayed, shoveled and piled on trees, lawns and perennial beds.
“The symptoms of salt injury include stunted yellow foliage, premature autumn leaf coloration, death of leaf margins, and twig dieback. On evergreens, needles may turn yellow or brown in early spring,” said Byers.
Salt damage is often confined to branches facing a street. Many plants can recover from an occasional salt spray. If it is a yearly occurrence however, death of the plant may result.
To prevent salt damage, do not plant closer than 50 feet from the road. If this is not feasible, screens of fencing or burlap can be used to deter salt sprays.
Snow from salted streets and sidewalks should not be piled onto plants. Salts not only injure plants directly but also can change the structure of the soil, causing the soil to become compacted.
“Where runoff of salt is unavoidable, flush the area around the plants in early spring by applying two inches of water over a two- to three-hour period, and then repeating three days later. This will leach much of the salt from the soil,” said Byers.
If salt spray from the road surface is a problem, use water to rinse the foliage and branches of any affected plants when salt spray is heavy and again in early spring. In problem areas, the salt levels in the soil can be tested. Contact the nearest county extension center for information on soil testing.
“The common salt used on roads and streets is sodium chloride. Alternative salts include calcium chloride and calcium magnesium acetate. Although more expensive, they will not harm plants if applied at low levels,” said Byers. “Another idea is to use materials like sand or sawdust on slick surfaces to improve traction.”
Where salt sprays can’t be avoided, plant salt tolerant species or cultivars that are resistant to salt damage.