Ladybug Blog Winter Salt Damage on Woody Plants February 10, 2009
Last week on February 2, 2009 Punxsutawney Phil saw his shadow. This date for winter weather prognostication has its origin in both European folkloric traditions and the Christian celebration of Candlemas. Six more weeks of winter was to be expected if Candlemas day was sunny. The same weather pattern was predicted if a hibernating animal, initially a hedgehog, was frightened by its shadow. This belief was brought to this country by German settlers during the 18th Century. They adopted the groundhog for their predictions as there are no native hedgehogs.
Be it startled ground hogs or terrified hedgehogs, New Englanders can usually expect at least six more weeks of winter.
This winter has been especially trying, bringing us freezing temperatures and weekly snow storms since mid December. With the storms come the snow plows and deicers. Starting in the winter of 2006-2007, the State of Connecticut implemented a new snow and ice control program, an all-salt regime using sodium chloride in solid and liquid form, in combination with liquid calcium chloride. Unfortunately the de-icing salts used during the cleanup efforts to maintain ice-free roadways, driveways, and sidewalks can cause severe damage to woody trees and shrubs.
Woody plants growing along roadways or side walks may be impacted by direct contact of deicing salt spray and by chemical changes in the soil due to a build up of salt ions that accumulate in the soil and are eventually absorbed by the plant roots. Salt ions can injure plants at any time, but late winter applications may accumulate and be more damaging since there is less time for winter snow and precipitation to leach away the salts.
Salt damage increases with the plant’s proximity to the road and is more severe on the side of the tree or shrub facing the road. The chlorides ions in these salts can be absorbed by roots and leaves resulting in the accumulation of toxic levels. Salt damage symptoms include marginal scorch of leaves, tip burn and dieback of buds and stems, foliar browning or the death of entire leaves, needles or twigs. In addition plants weakened by excessive salt exposure can be more susceptible to disease and pest problems.
These are some methods that can be employed to remedy the impact of deicing salts on trees and shrubs:
Wash salt spray off plants with fresh water as soon as possible after salt exposure.
Flush out excess salts from the root zones. This can be done as soon as the ground is no longer frozen. Repeated applications may be necessary.
Construct a physical barrier made of plastic, burlap, or snow fencing , or a berm of soil between the pavement and the plants
Plant salt tolerant plants in high risk areas.
Maintain vigorous growth in plants.