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.