Salting to get snow and ice off roads, driveways and walkways can seriously damage trees, shrubs and grasses. Outdoor plants may be dormant, but their roots still absorb moisture from the soil; salt concentrations around them result in their losing water instead of absorbing it.
It's called osmosis: The moisture in the roots moves out to dilute and equalize the salt concentration in the soil. The plant can be seriously damaged, even killed.
Several relatively small things can be done to reduce salt damage. One is to use, lightly, urea, a commercial nitrogeneous fertilizer, instead of salt. Washed from a walk or driveway, urea enriches the surrounding soil -- although heavy applications can ruin the lawn. It's non-corrosive and doesn't damage asphalt or concrete. It's a available as crystals or pellets; the pellets are preferred for ice removal.
Don't try to melt six inches of snow with salt or urea, but shovel first. The salt or urea should not be washed or shoveled off the pavement after snow and ice are melted: Leave it there, ready for the next snowfall. If you do have to shovel after applying urea, don't pile it on landscaped areas.
Where large amounts of salt are used, try to devise a gutter along walkways and driveways to carry it off as it dissolves with water.
Where salting has been done, incorporate organic matter into the soil at planting time. Use organic mulches around salt-sensitive plants to absorb the salts before they get down into the root again.
Plants most likely to be damaged by salt include roses, boxwood, black walnut, red maple, sugar maple and bluegrass.
Symptoms of salt damage are usually like those caused by drought: all plant parts become stunted. Tips of leaves may be burnt and edges browned, especially where drainage is poor.
Look at trees near school and commercial bus stops and low places along highways where salt is washed down to tree roots: Trees up to 30 feet from a highway have been badly damaged by salt seeping down to their roots.
Q. We bought a dwarf red maple in the spring. It was red and beautiful but turned green in early summer and stayed that way. Is there a way to make it stay red all summer?
A. Most red maples, including the Japanese maples, are that way. It is the way they are built (their genetic makeup) and there is nothing that can be done about it.