Winter weather and plant injury

Posted March 21, 2013 at 11:12 am

Road salt comes in handy when streets, sidewalks and driveways are slippery with ice. It’s not so handy when it splashes onto plants or soaks into the soil.

Salt spray and salt runoff can damage plants, said Jennifer Schutter, horticulture specialist for University of Missouri Extension.

“Salt spray kicked up by moving vehicles is deposited on plants, causing dehydration of the plant tissue,” Schutter said. It can cause bud death and twig dieback. Clusters of twigs form on branches where the dieback occurred. This formation, called “witches broom,” shows when growth starts in the spring.

Salt runoff can wash into the soil, where plant roots may absorb it, causing toxic effects. High salt concentration can also prevent roots from taking up water, killing the plant.

“Symptoms of salt injury include a blue-green cast to the foliage, marginal leaf burn, reduction in leaf, flower and fruit size, stunting and a general lack of vigor,” Schutter said. “During late summer and periods of hot, dry weather these symptoms will become more severe.”

In areas where salt spray and runoff are a regular problem, it’s a good idea to plant salt-tolerant species, Schutter said. You could protect plants with a physical barrier such as plastic, burlap, plywood or window screen. Avoid planting in drainage areas where salt runoff can accumulate.

Soil that’s been saturated with salt should be watered heavily in the spring, Schutter said. However, she notes, this will only work in soil with good drainage.

As with most things, prevention is the best practice. Keep salt and other ice melters away from plants and soil, use them sparingly, and purchase those that are more environmentally friendly.