When Salt (sodium chloride) is used during the Winter to de-ice our streets, it can cause severe damage to a wide variety of roadside plants in your landscape. The core of the problem is the result of salt dissolving into runoff water from melting snow which leaches into the root zone of your plants. Additionally salted snow often ends up being pushed onto lawns and parking strips by snow-plows which, when it melts, causes even more damage to your landscape.
Plant sensitivity varies widely depending on the species. Some plants are highly resistant, some cannot tolerate the slightest salt imbalance. This is the time of year to watch for signs of salt damage as all that snow melts!
Watch Out For:
- Noticeable Delay in Spring “budbreak”/flowering
- Stunted Foliage and Noticeably Small Buds
- Reduced New Shoot Growth
- Tip or Marginal Foliage Browning
- Crown Thinning or Crown Tufting
- Premature Fall coloration and defoliation (losing leaves early)
- Also, beware! Salt-Damaged plants are prone to attacks from insects that bore holes and from pathogenic fungi!
Typical Spring behavior is for the Crown of your landscape plants to “shoot” and fill in. If you see Crown dieback instead, this could be another sign that your plants have salt damage.
NOOOOO! Why Does This Happen?
I know… We’re upset about it too! But there’s hope. Here’s the information we’ve gathered, we think it will help.
Sodium Chloride, when mixed with water, “burns” plant roots and foliage due to it’s acidic pH of around 5.5, which is relatively acidic when compared with your plants “neutral” pH preference of around 7 (like water). The acid “burning” damages the cell walls in your plant roots and foliage effectively disabling new growth and the critical functions of those cells. In turn this causes the plant to take in less nutrients (if roots are damaged) or have less capacity to collect energy from the Sun (if the foliage is damaged) or both! In the end, many plants will succumb to salt damage and die if not treated.
What Can You Do?
It should come as no surprise that by selecting plants, trees and shrubs that have a natural resistance or tolerance to salt, you can protect your landscape from severe salt damage. The problem really occurs when you’re ready to plant, but don’t know what to plant. So we put together the following list for you!
- Norway Maple
- Paper Birch
- Russian Olive
- Honey Locust
- White Poplar
- Quaking Aspen
- Black Cherry
- White Oak
- Red Oak
- Black Locust
- Weeping Willow
- Blue Spruce
- Mugo Pine
- Australian Pine
There are several techniques that can be used to protect your landscape from salt damage, however while they do minimize the risk, they are certainly not infallible!
- Protective Barriers: Burlap, Polyethylene, Wood Boxes & Planters (does not protect foliage well from salt splash!)
- Cultural protection: use calcium chloride instead of sodium chloride for de-icing. It’s much less toxic for your plants and also for the environment. You can find calcium chloride at Giordano’s! Sand is another alternative, but not as effective
In a word, Gypsum! Gypsum (calcium sulfate) has been used to improve soil structure by combating/neutralizing the sodium ions present in the affected soil. The chemical process that occurs essentially makes the salt impossible for the plant to absorb or be burned by.
Use: Gypsum can be applied to the surface of your landscape with a lawn spreader or using a “deep placement” technique similar to the application of a granular fertilizer. We recommend between 20 and 40 pounds of gypsum per 100 sqft of soil surface depending purely on the amount of salt that has leached into your root base. Depending on the damage, it may be necessary to apply spot treatments that are much stronger in certain areas or spread in a “gradient” fashion.
PLEASE reach out to us if you need advice!