Outdoors

Ice melt can be harmful to trees, plants

By Herald-Whig
Posted: Jan. 31, 2019 12:01 am Updated: Feb. 1, 2019 12:56 am

QUINCY -- John Grievers watched his neighbor liberally toss ice melt across his driveway and sidewalks after clearing away the snow, and all he could do was dumbfoundedly shake his head.

"That man is killing everything," Grievers said to himself.

He should know. With a master's degree in botany, Grievers worked most of his career as a landscape consultant and horticulturalist before retiring two years ago.

Each time winter weather hits, Grievers watches people ruin their plants and trees by using too much ice melt.

He hopes eventually some of them will get the message.

"Ice melt is made of elements designed to do damage," Grievers said. "They break down the ice and can cause problems for the surfaces they touch. Much worse, they kill things you don't openly see. You can't just throw ice melt wildly. You have to be strategic with how you use such compounds.

"You can't let ice melt near your plants or trees and grassy areas. It's simply lethal."

The cheapest and most commonly used form of ice melt is rock salt -- also known as sodium chloride -- but it also is the worst for your landscape.

Plants use sodium in miniscule amounts, and when there's a high concentration of salt in the soil, it can pull water out of the plants, causing them to shrivel up and die.

Sodium also affects soil texture by "tightening up" the small particles of clay, causing poor drainage and killing much of the soil biology.

"If you sweep the ice melt off your concrete surfaces and into your yard, you're killing plants," Grievers said. "Here's a simple rule of thumb: Just don't do it."

The long-term effects will become noticeable.

After exposure to salt spray, evergreens may show immediate effects, while deciduous plants may not show damage until the next growing season.

Symptoms include yellowing or dwarfing of foliage, or dieback of twigs. Damage is usually more noticeable on the side facing the drift.

If possible, prune dead or deformed branches and wash away any surface salt residues. Treat for soil contamination if exposure has been long and heavy.

To alleviate the adverse effects of salt in the soil, apply gypsum as a preventive measure. For moderately contaminated soil, or where it is anticipated, apply 100 to 200 pounds of gypsum per thousand square feet over the affected area. This treatment can be made every three years.

For heavily contaminated soil, apply up to 700 pounds of gypsum per thousand square feet, or 150 to 200 pounds per year for up to three years.

Powdered gypsum should be used to promote its solubility and movement into the soil. Gypsum is a naturally occurring substance that will not pollute the environment. It is frequently used as a soil conditioner or for clearing muddy water in ponds and is available at garden centers in 50 pound bags.

The Missouri Department of Conservation offered a checklist of things to think about when applying ice melt in order to better protect trees and plants:

º Remove ice by mechanical means if practical.

º Create drainage channels or barriers around plants where ice melters are used.

º Use only the amount of ice melting chemical needed to do the job. Practice moderation.

º Use dark-colored abrasives as an alternate or supplement to chemicals.

º Use calcium chloride rather than sodium chloride when fertilizers are not practical.

º Apply gypsum if sodium chloride contamination is anticipated.

º Be especially careful in applying salts in late winter or early spring, or when the ground is not frozen.

Some species are more likely to be affected by the sodium chloride found in rock salt.

Here are the ones to watch closely: Pines, balsam fir, locusts, oaks, maples (including box elders and tulip poplars), willows, fruit trees, rhododendrons and azaleas.

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