Extension Communications
Extension 4-H Youth Building
Ames, Iowa 50011-3630
(515) 294-9915
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Extension Communications |
12/24/03
Contacts:
Linda Naeve, Reiman Gardens, (515) 294-8946, lnaeve@iastate.edu
Jean McGuire, Continuing Education and Communication Services, (515) 294-7033,
jmcguire@iastate.edu
Reiman's Pick for the week of Dec. 22, 2003
Pick the Right Salt for Your Sidewalks and Landscape
Linda Naeve
Extension Coordinator
Reiman Gardens
It wouldn't be winter in Iowa without snow and a bit of ice mixed in. A beautiful snowfall in December sets the holiday stage, but by January, it quickly goes from beauty to burden. However, snow does have some good qualities. Plants and school-aged children like to see snow because a good, six-inch layer is perfect for school closings and insulating protection.
Snow is an excellent insulator for plants against the damage caused by low temperatures and strong, desiccating winds. Research has shown that the temperature below a layer of snow increases by approximately 2 degrees Fahrenheit for each inch of snow accumulation. Even with sub-zero temperatures, a continuous blanket of snow over a strawberry bed will protect the flower buds that have already formed. Snow is also a source of needed moisture for landscape plants.
As with most good things, too much of anything can be harmful. Several inches of heavy snow piled on evergreens and multi-stemmed shrubs can break their branches. Carefully remove it by gently brushing it away with a broom.
The real winter enemy for plants and people is ice. Heavy ice accumulation on branches and stems can cause them to snap and break under the weight. Unfortunately, there is not much we can do to prevent the damage. We prevent slippery, dangerous ice on streets and walkways by applying de-icing compounds and/or abrasive materials. In doing so, we may be causing problems for our ornamental plants.
This week's Reiman's Pick, calcium chloride, is a de-icing material that is less harmful to plants than the widely used sodium chloride. Calcium chloride is a good de-icer because it dissolves easily and effectively at extremely low temperatures (-20 degrees Fahrenheit). Sold in pelleted form for home use, calcium chloride is applied in a liquid form for road maintenance. Occasionally during really cold weather, the Iowa Department of Transportation (DOT) crews apply a very thin layer of liquid calcium chloride prior to a predicted snow and ice storm to inhibit the bonding of snow and ice to the pavement, making it easier for snowplows to clear roads.
The Iowa DOT doesn't routinely use calcium chloride on our highways because it costs one and a half times more than sodium chloride and it is more corrosive on concrete. Sodium chloride, commonly referred to as table or rock salt, is the de-icer most frequently used on Iowa highways.
Unfortunately, most de-icing salts can damage lawns and landscape plants, especially when excessive amounts accumulate in the soil. When salt levels are high in the soil, plants are unable to absorb sufficient water, even though soil moisture is plentiful. Damage can also occur when the salt brine and residue covers dormant stems and buds of deciduous trees and needles of evergreens. To avoid salt damage, avoid plowing or shoveling salt-laden snow onto turf or under trees and shrubs. In the spring, thoroughly and heavily water lawn areas near streets to flush the salt from the plants' root zone.
There is not a perfect solution when dealing with icy roads and sidewalks. The staff at Reiman Gardens keeps walkways safe with calcium chloride and are careful to avoid getting it on turf areas and landscape plants.
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Editors: No photo is available for this week's column.