Salt Damage

Characteristics

Salt damage on trees and shrubs often goes unnoticed until severe signs and symptoms are present. Salts can impede growth, cause foliar browning, and sometimes lead to plant death.  

There are two ways salt can damage trees and shrubs: from spraying on foliage, and accumulating in the soil. Salt spray damage occurs when salt particles are sprayed onto plant foliage by passing vehicles. Salts that ends up on foliage can cause severe browning. Salts that accumulate in the soil damage trees and shrubs by pulling water away from roots. Soils with high levels of mineral salts can pull enough water away from roots to mimic symptoms of drought stress.

Signs & Symptoms

Symptoms of salt damage include: leaf burn, yellowing of tree needles, wilting, no flowering, and early fall defoliation.

On coniferous trees and shrubs, salt spray damage causes needles to turn brown where spray injury occurs. Affected needles may drop prematurely leaving bare branches. Over several years, the amount of new needle growth is reduced.

On deciduous trees, salt spray can kill dormant buds before they open. After leaf emergence, salt damage symptoms on deciduous trees include: faded green leaf color, smaller stunted leaves, leaves with scorched margins, thin crowns with dying twigs and branches, and early fall colour.

Treatment & Recommendations

The best control measure for salt damage is to prevent it. When planting trees, select species that are more salt tolerant. Plant trees and shrubs further away from roads and sidewalks to reduce salt injuries. Wash salt off trees in early spring to reduce salt on branches. Snow fences can reduce snow and salt pushed near trees during the winter. Plants that exhibit dieback from salt damage can be pruned in the spring.

Applying gypsum to salty soils displaces the sodium and lessens the dispersion of soil particles. Gypsum can mitigate the loss of soil aggregates, improve soil aeration, and help with soil drainage problems.

For further information on salt damage, talk with one of our qualified arborists.