Will Salt Kill Shrubs If Poured Around the Base?

Salt in Roots

• Salt consists of sodium and chloride, and the ions of both separate when salt comes into contact with water. The sodium ions rapidly replace the other nutrients such as calcium, magnesium and potassium in soil, making them unavailable for plants. The chloride ions start to absorb all moisture in the soil and the roots, resulting in dehydration. Chloride ions are transported to foliage where they disrupt photosynthesis and chlorophyll production.

Salt on Plants

• The exposure of above ground shrub parts to salt causes as much damage as when salt is applied to the roots. This commonly happens when shrubs are in the way of de-icing trucks or growing in coastal areas. Symptoms of above ground plant exposure include disfigured stems and foliage and reduced overall plant size. The damaged shrub areas start to produce tufted new growth referred to as witches broom. Foliage is burned, scorched or brown. There may be a visible accumulation of salt on plant foliage.

Reducing Damage

• When planting shrubs in coastal gardens, make sure the plants are not exposed to salt spray. Place temporary burlap fencing around shrubs planted close to roads to protect them from salt where the de-icing trucks are likely to cause damage. Keeping shrubs in good health by providing adequate fertilizer and water will make plants more tolerant of temporary salt-induced damage. In saline soil, the best option is to use plants that are salt tolerant or halophytic in nature.

Improving Saline Soil

• High levels of salinity in soil adversely affects the growth of shrubs in the same manner as when salt is poured directly in the plant base. Fix soil salinity by adding organic material to soil, as this increases moisture retention capacity in soil and improves structure. Water shrubs in saline soils deeply as this helps to flush out the excess salt from the soil. Mulch the shrubs to prevent salt buildup around root zone. Conduct soil tests regularly and use fertilizers as indicated by test results.