In most winters, we would have had to wash salt off our cars several times by now. How many times have you had to so far this year?
Some areas of the country are experiencing major storms, and road salt consumption is probably comparable to or a bit ahead of previous years. This has led to some landscape industry conversations about protecting your trees against road salt damage. Considering that winter snow and the resulting use of road salt is inevitable, I’d like to address any concerns that you may have now, so you can take preventive action if necessary.
The most beneficial study that I used to research this blog was published recently by Virginia Tech and its Cooperative Extension. But, isn’t Virginia down south where it’s warm, you ask? It’s down south but not so far south that they don’t get ice and snow. Maybe not as much or as often as we do, but they still get it. Some of the state is also along the Atlantic coast with its salty air and spray.
Most of the salt we receive is in the form of salt spray as the plows and salt trucks go past our houses. Where roads are at the top of a hill and your yard slopes down from there, you may have salty soil. The snow plow piles snow, mixed with salty brine, at the top of the hill to leach into the soil and then down the hill, accumulating at the bottom.
I already recommended wrapping particularly sensitive trees or shrubs sited near the road with burlap or building a wood structure to protect them from salt spray. Here are some other steps you can take to reduce salt spray damage:
- Design planting areas to reduce exposure of trees and shrubs to salt spray. Establish windbreaks to prevent “wind tunnels” that can carry aerial salts farther and at higher wind speeds. Use salt-tolerant shrubs or herbaceous borders (especially denser evergreens) as windbreaks to help intercept aerial salt drift before it reaches sensitive plants.
- Group tree and shrub species to shield them from wind and drift, with the most tolerant species in higher exposure areas to shield moderately tolerant species.
- Maintain appropriate soil fertility and moisture conditions to reduce additional stresses and help combat desiccation. If feasible, rinse salt spray off trees and shrubs after storms and high winds. Rinse again in early spring to remove salt residue from tender buds and leaves.
- Plant in spring when locating trees and shrubs near roads on which de-icing salts are used. This allows plants more time to become established prior to salt exposure. Trees and shrubs that are susceptible to salt damage should be located at least 50-60 feet from roads.
- When practical, use cinders, fly ash or sand for de-icing.
- Select and plant salt spray tolerant trees and shrubs. Avoid plants, such as azaleas, that are considered especially sensitive to salt spray.
- Fertilize at rates recommended by soil analyses and fertilizer labels.
- Keep plants healthy because healthy plants are more tolerant of salt damage.
If you aren’t into gardening and lawn care, we have a full staff of designers and horticulturists who would be happy to visit your property, analyze your current plants’ potential for salt damage and make recommendations for dealing with the problem. We have kits to test soil salinity if that’s a concern, and we know the signs of salt damage.
Over the years, we haven’t seen widespread de-icing salt damage. Most has been limited to young plants in the path of salt spray. This can be mitigated by wrapping the trees in burlap until they are able to tolerate salt spray. The other cause is that old nemesis – wrong plant in the wrong place.