By Judy Bernard, Master Gardener
With a retaining wall and a paved boulevard, we have never had to worry about salt damage to our lawn and plants. Now, living in a new development with grass growing right to the street and grass boulevards, salt damage from road salt is a new fact of life. We have all seen the damage to certain trees (cedars especially) where the foliage has turned brown from salt spray. Sod gets chewed up from the plows and grass at the side of the road turns brown as well.
In addition to the mechanical damage from snow clearing, there are some other things which are happening to cause this damage:
- The salt spray causes the foliage to dry out. On deciduous plants, the buds can be desiccated by the salt.
- Salt absorbs a lot of water. Even if the ground is wet, if there is salt in the ground it is preventing the plants from accessing the water.
- Salt breaks down into its component ions of sodium and calcium. The calcium gets absorbed into the leaves preventing photosynthesis. The sodium prevents the roots from taking up necessary nutrients.
In early spring there are things we can do to help our plants to recover from and to mitigate the effects of salt and salt spray:
- Gently rake and remove as much of the salt and sand that has been left behind around the curb area after the snow has melted. For the rest of the lawn, you need to wait until the ground has thawed and dried out; you don’t want to leave foot impressions in the lawn.
- Hopefully we will have lots of rain to wash the salt spray from the boughs of the plants, and to wash that water away. If not, then wash the spray off of the plants.
- Water, and lots of it, applied slowly over several days is the way to rinse the salt that has gotten into the soil out. It takes 7-8cm of water to rinse 50% of the salt out of the soil; 13cm to wash 90% out. If we have a dry spring, and don’t get that much water over a few days, then where possible augment rainfall with water.
As we get ready for winter we can take steps to protect our gardens in the fall:
- Put a good layer of mulch in the form of leaves over the perennial beds close to the roads. This can then be removed in the spring, taking much of the salt with it.
- Protect trees and shrubs with burlap wrapping.
- Put up a barrier or screen to prevent salt runoff back onto your property.
- Use other materials around your home, like sand or salt alternatives to provide traction in icy conditions.
- Use salt-resistant plants close to roads and sidewalks.
Now, let’s hope for lots of spring rain to freshen up our gardens and get the growing season underway!
The following web sites will give you more information about what to look for as well as having suggestions for salt resistant plants:
Before and after the same spot of lawn.