Salt spray causes brown foliage on evergreens or "witches'-broom" on deciduous plants. A witches'-broom is a cluster of twigs that forms on a branch. Prolonged exposure to salt spray can lead to dieback.
Salt spray can drift to plants from nearby roads as the tires of passing cars kick up a salty spray. The water evaporates, leaving a salt residue. Short plants can be protected from the spray with tar-backed burlap screens. Larger plants can not be protected. Road salt can also be a problem when salty run-off accumulates salt in the root zones of plants growing near the road.
Salt can injure landscape plants when salt used on porches and sidewalks is shoveled or swept onto nearby shrubs, where it accumulates on the foliage or in the root zones. Most chemical deicers will have the same injurious effects, though calcium chloride is not as harmful as sodium chloride. Fertilizer is sometimes used, but it, too, can build up to toxic levels. Sand and ashes are not toxic but have the disadvantage of being easily tracked into the house.
A third source of salt can be softened water running into septic systems. Evergreens will display browned foliage that forms a rough spiral as it moves up the tree. Trees may grow well for a number of years and then show symptoms when their roots finally reach the source of the salt.
Tree species vary in their susceptibility to salt injury. A susceptible species such as white pine should not be planted near roadsides where salt will be applied.
|Visual title - Visual size||Visual title - Visual size|
|Salt damage, from road salt - 43K||Salt injury, burlap screens used as winter protection - 54K|
|Salt injury on spruce - 24K||Salt injury on spruce - 42K|
|Salt injury on spruce - 40K|