Deicing salts used on Northern roadways can cause extensive damage to plants, shrubs and trees, as well as turf grass. Salts, calcium chloride, and other deicing chemicals are deposited well up into your property by aerial spray application, snow plowing and splash from passing vehicles. Damage is evident primarily in the first 30 to 60 feet along the roadway, but can cause burn to sensitive plants 300 feet or more from the road.
The worst damage is caused by air borne salt from application trucks and traffic spray. Then when the deep snowbanks full of deicer melts, salt is deposited in the soil. Plants nearest the roadways are sometimes exposed to high concentrations of salt and chloride in the soil, which is absorbed by the roots. Eventually the roots can become so damaged that they will not take up water.
Your best defense is to use plants that can tolerate high salt levels. In the hellstrip, boulevard, or along curbs you should use plants that are highly tolerant of roadsalts. But there are other things you can do that will help.
- Salt will accumulate in heavy concentrations where the soil is depressed and in drainageways. Planting areas should be level or graded to allow for runoff
- Plants growing in soil with poor drainage such as clay or compacted soil are more susceptible, soil should be amended to improve drainage
- Water heavily to move salt through the soil and away from the root zone. The soil must be well drained to accomplish this
- Mulch planting areas heavily before winter
- Temporary barriers of burlap can help protect plans from the worst exposure
- Select plants that are tolerant of the conditions
- Plants that are not fully hardy for your growing zone will be more severely injured
- The salt tolerance of plants is increased by a soil that is rich in organic matter. Amend your soil with compost or peat, and add gypsum at a rate of 10-20 pounds per hundred square feet.
- Well maintained plants will hold up to the stress better. Properly prune, water and fertilize your plants. (Remember that drought tolerant or native plants prefer NOT to be watered and fertilized. Maintain plants according to their specific needs.)
Well into your property, plants can be damaged by aerial salt exposure. When selecting plants, avoid using the most sensitive near roadways.
Commonly used large landscape plants that are most sensitive to aerial salt:
- Eastern White Pine Pinus strobes
- Yew Taxus spp
- American Arborvitae Thuja occidentalis
- Japanese Barberry Berberis thunbergii
- Dogwood Cornus spp
- Spirea Spirea spp
- Rododendron/Azalea Rhododendron spp
Instead, consider these more salt tolerant landscape plants:
- Honeylocust Gleditsia triacanthos
- Pfitzer Juniper Juniperus chinensis ‘Pfitzerana’
- Alpine Currant Ribes alpinum
- Mock Orange Philadelphus spp
- Bush Cinquefoil Potentilla fruticosa
- Common Snowberry Symphoricarpos
There are many other salt tolerant shrubs and perennials for garden plantings. See the Next Page for ideas.
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