|Just as salts cause vehicles to corrode, it can also create problems for landscape is the warning of Patrick Byers, a horticulture specialist with University of Missouri Extension. Often when shoveling sidewalks and driveways that have previously been salted, people are oblivious to where they are throwing the snow and they pile it around trees and on shrubs 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. Salts not only injure plants directly but also can change the structure of the soil, causing it to become compacted.
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.
"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," Byers said.
Alternatives to harmful sodium chloride, the common salt used on roads, are 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. It should be noted that the sugar maple (Acer saccharum) 'Legacy" is not tolerant of salt while several species of oak including the Missouri natives swamp white oak (Quercus bicolor) and Shumard oak (Quercus shumardii) are.