De-icing salts are essential in keeping roads and sidewalks dry and safe during the winter months. While this is great for keeping roads clear for travel, salt can take a toll on your trees and shrubs if they are located near salt-treated pavement. Keep reading to learn how salt can affect your trees, and what you can do to reduce the harm.
How Does Salt Damage Trees?
Salt spray from cars cause bark discoloration on your trees and shrubs. Damage from airborne salt is more obvious on evergreens. Since evergreens keep their needles year-round, it’s easy to pinpoint conifers that have been affected because of their pale green and yellow needles.
Road salts can also leach down into the soil and impact tree root systems. Melting ice and snow transports salt below ground-level, increasing the salt content in the soil. This alters the trees’ mineral nutrition balance and soil structure. This makes it tough for roots to uptake water and sometimes can take the water from the roots. Trees and shrubs do not require as much water during the colder months, so the effects are not immediate. It’s when the leaves begin to emerge in the spring that the salt-saturated soils become a larger issue for growing trees.
What Can be Done to Lessen the Impact?
While there’s not a lot you can do about the application of salt by the city, you can reduce some of the negative impact by watering your trees when possible throughout the winter. It’s also beneficial to provide your trees with extra water in early spring—this will help flush the salt from the soil.
If you salt your own sidewalk and driveway, you can choose a type of road salt that is less harmful to plants. Sodium chloride is the most commonly used road salt because it’s inexpensive and effective. However, sodium chloride is harsher on your trees and shrubs. Choosing a different type of salt like Calcium Chloride, is more expensive but less damaging to your trees and shrubs.
If you use sodium chloride, be cautious not to overdo it. The less you apply, the less salt that will trickle down into your soil as the ice and snow melt. You can also mix sodium chloride with sand or sawdust. These materials help with traction and reduce the amount of salt needed.
You can also choose to plant salt tolerant trees in areas that are close to pavement. Trees like hedge maples or pin oaks are excellent choices.
Your trees and shrubs are an important asset to your property. Follow the advice above to help protect your specimens against the effects of de-icing salt. If you think the health of your trees are suffering from extensive airborne salt or salt that has leached into the soil, consider having a certified arborist come take a look. They can assess what’s actually going on and suggest treatment plans to get the health of your trees and shrubs back on track!