From foot-deep white blankets to delicate flurries, we know the drill after any snowstorm: spread winter salt to avoid icy mishaps. It’s a quick fix to keep us safe, but rock salt can leave trees and other landscape plants vulnerable to damage.
Know the signs of rock salt damage on trees to protect them.
According to George Barth, ISA certified arborist at Hartney Greymont, a Davey company, tree symptoms from rock salt damage vary based on the type of tree.
“On evergreens, damage is more obvious to the naked eye,” says Barth. “Salt residue can cause yellow needles. For deciduous trees, the symptoms are less obvious. When snow has piled up near a tree, salt can seep into the tree’s roots and result in dry soil, bark discoloration or canopy dieback.”
Look for salt damage where snow has piled up near trees to see if treatment is necessary. Once any of these symptoms are spotted, restoring tree health requires management from you and your local arborist.
There are steps to take to protect trees and plants
- If you spread salt, choose one with calcium chloride, which is less harmful to plants than salt with sodium chloride. If you must use sodium chloride, then mix it with sand, sawdust or other similar materials, which aid in traction and reduce the amount of salt spread.
- Extra winter watering of road-side trees, when possible.
- Rinse away salt off of tree trunks when the snow clears.
- To rid the soil of any lingering salt, your local arborist can remediate and replace salt-saturated soil with organic matter in spring.
- Barth recommends a layer of gypsum in late fall and early winter to help protect plant and tree roots from salt damage.
- Fertilizing trees in the spring provides nutritional support to help cope with wintertime salt damage.
Salt-tolerant Trees for the Northeast
According to Barth, common salt-tolerant trees include white oak, red oak, Austrian pine and Colorado spruce.
Across all regions, healthy, mature trees and trees with thick bark tend to withstand damage well. Trees that are stressed from storm damage, harmful insects or disease infestation suffer more damage from rock salt.
Remember, careful planning and placement can limit all plants’ exposure to salt.
To find an arborist in your region, visit https://www.davey.com/residential-tree-services/find-a-local-office/.