Gardening: Ways to ward off salt damage to your plants and trees

Nancy Szerlag
Special to The Detroit News
Road salt runoff can damage plants, but there are ways to help prevent the issues.

With the arrival of freezing weather comes salt-covered roads, streets and sidewalks. And that salt can cause widespread damage to trees, shrubs, grass and other plant life. While the salt may be spread a long way from the greenery, it can travel a good distance in the form of salt spray churned up from fast-moving cars and large trucks. 

Salt runoff also washes into the soil and can be taken up by the roots of plants causing disfigured foliage, stunted growth, severe decline and even death. Many homeowners have seen and are aware of the damage to shrubs and plants but do not realize that trees can also affected.

Signs of salt damage are usually evident on turf, smaller plants and shrubs in spring but in the case of trees, it may not be visible until late summer and in some cases decline may not be visible for years. Homeowners often misdiagnose the cause of damage and treat the tree for pests or disease. 

There are steps you can take to help ward off salt damage, and here are some measures recommended by Tree Care Industry Association.

--Avoid the use of de-icing salt unless necessary and do not over apply it if used.

--If salt is used, reduce the amount by mixing it with abrasives such as sand or wood ashes.

--Use de-icing alternatives such as calcium chloride or calcium magnesium acetate.

--Improve the drainage of soil by adding composted wood chips or bark mulch and thoroughly leach salt residues from soil by flushing with water in spring when the soil thaws.

Some other suggestions are:

--Hosing down bark on trees and shrubs in early spring. Erecting barriers, such as screening with burlap, helps protect the foliage of shrubs from salt spray.

--When the frost has left the ground, irrigating the soil with 2 inches of water over a period of an hour and repeating the procedure three days later.  

--Gypsum (Calcium Sulfate), a natural mineral, spread on the surface of the soil or turf and watered in, will help to mitigate the effects of sodium in the soil. It can be applied to damaged areas using a fertilizer spreader at a rate of 20 lbs. per 100 square feet, before flushing with water.  Applying the gypsum in fall will help reduce the damage from the get-go, so put it on your to-do list for next November.

Nancy Szerlag is a master gardener and Metro Detroit freelance writer. Her column appears Fridays in Homestyle. To ask her a question go to and click on Ask Nancy. You can also read her previous columns at detroitnewscom/homestyle.