Most people are aware of the corrosive effects of salt on cars and trucks but may not be aware of the damage that winter salt from roads and walkways causes to trees and plants.
When salty road spray from passing vehicles and plows contacts trees and plants, the salt enters plants through the cells. Buds and twigs lose cold hardiness and are more likely to be killed by windy and freezing winter weather. Salt accumulation in the soil also causes injury when salt-laden snow is plowed off streets and sidewalks onto adjacent lawns and beds. Damage to plants from salt injury occurs throughout the next growing season, especially visible during the times of new growth and drought.
The symptoms of salt damage are smaller than usual leaves, tan-brown and yellow foliage, browning of leaf margins, twig dieback and premature autumn leaf color. Conifers and evergreens are very susceptible to salt injury showing browning of old and new needles. If salt is excessive in the soil, new leaves and needles may start to grow only to die and turn brown as the excessive salt accumulation shuts down water transport. In severe situations, salt damage could be lethal or show damage for several consecutive years.
Salt-tolerant deciduous trees include ash, birch, honeylocust, poplar, red oak, tamarack (larch), weeping willow and white oak. Salt-tolerant shrubs include, cotoneaster, hydrangea, mockorange, northern bayberry, pea shrub, potentilla, serviceberry, winterberry and most shrub roses.