by Elaine Mills, Extension Master Gardener
Photos by Elaine Mills, unless otherwise credited
Winter weather can pose a challenge for our garden plants. Even in years when heavy snow doesn’t weigh down evergreen foliage or ice accumulation doesn’t cause broken branches, the spray from preventive applications of salt and other de-icing products to roadways can cause damage to plants, ranging from desiccation to death.
Learn more about salt pollution by attending National Salt Week webinars presented by Arlington County.
Impact of Salt on Plants
In Virginia, rock salt (sodium chloride) is the primary de-icing chemical applied to roads because it is inexpensive, easy to store, and effective both in preventing ice from forming and in melting existing snow and ice to improve traction during inclement wintery weather. Sometimes liquid magnesium chloride or sodium chloride brine are used as pre-treatments for road surfaces in anticipation of winter storms. Spray created by fast-moving traffic and wind carries tiny water droplets containing dissolved salts from treated roads onto plants. When the droplets evaporate, sodium (Na) and chloride (Cl) ions penetrate the plant tissues causing direct damage referred to as “salt burn.”
When accumulated ice and snow melt, high levels of soluble salt in the runoff break down soil structure by causing small soil particles to wash into the pore spaces between larger particles. This not only makes it difficult for soil to absorb and drain water, but it also results in very high soil pH (above 8.0). Over time, the roots of plants growing in this soil become unable to take up water and nutrients, and cytotoxicity leads to cell damage. Stressed plants then become more vulnerable to pests and diseases.
Jospeh LaForest, University og Georgia, Bugwood.org
Treatments and Salt Alternatives
Virginia Tech advises that prompt treatment of affected plants with a gentle water rinse soon after initial exposure may reduce damage from salt spray. Treatment of salt in soil is more complex, involving soil tests, an application of granular gypsum, and flushing with heavy irrigation. Unfortunately, this procedure does not always reduce salts to acceptable levels. (See Publication 430-031, Trees and Shrubs that Tolerate Saline Soils, Salt Spray and De-icing Salts for details).
Some homeowners use Calcium Magnesium Acetate (CMA), an ice melt alternative to rock salt on their sidewalks and driveways. This is a less corrosive product that is considered safer for plants, pets, and wildlife. Gardeners can also consider using homemade alternatives, including cooled wood ash or rubbing alcohol, and traction improvers such as sand, gravel, or wood shavings. (See a recorded presentation on “Managing Salt Damage in Your Garden”, beginning at 0:13:03, for details.) However, the best—and least expensive—approach for avoiding salt damage is to use protective garden practices or to select salt-tolerant plants.
Protective Garden Practices
Edgeplot, CC BY_NC_SA 2.0
Gardeners can site their plants behind fences that act as windbreaks to intercept salt drift. Temporary burlap fencing or other barriers can be erected beside the road in winter. Another option would be to use signage along roads to prevent plows from piling treated snow and ice on adjacent plantings.
Other protective practices include improving soil structure by adding organic matter, irrigating infrequently but deeply (1 inch of water per week) to promote deep root systems that can resist salt damage, and using mulch around plant roots to prevent evaporation. Planting uphill, in berms, or in raised beds can allow any salty water to flow away from plant roots. The most sensitive plant species should be planted 50 to 60 feet away from any paving.
Courtesy of George Weigel
Salt-Tolerant Native Plants
Another option for planting garden beds adjacent to roads or paving is to select plants that are naturally more salt-tolerant. Some species have physical characteristics, such as leaves with a thick, waxy cuticle, that protect them from salt spray. Others have developed physiological adaptations that allow them to manage high salt levels. They may prevent salt from being absorbed by their roots, they may excrete any salt they absorb through specialized glands in their leaves, or they may store salt in vacuoles within their cells, so it is isolated from any metabolic processes. An interesting report published in the International Journal of Molecular Science describes how specific plant genes have been shown to improve salt tolerance by affecting the response to salt stress by roots, stems, leaves, and flowers.
Halophytes, plants whose native habitats are coastal dunes or saltwater/brackish water marshes, are good choices for garden beds that may be exposed to salt spray. Our website resources on “Best Bets” plants summarize the results of a survey of 11 lists of salt-tolerant plants compiled by cooperative extension offices, public gardens, and other organizations from New England to South Carolina. In that comparison, eastern redcedar (Juniperus virginiana) is the tree that is universally reported to be tolerant of both salt spray and salty soil. Sweetbay magnolia (Magnolia virginiana), downy serviceberry (Amelanchier arborea), and American holly (Ilex opaca) appear on four to five lists each, while river birch (Betula nigra), black gum (Nyssa sylvatica), white oak (Quercus alba), and red oak (Quercus rubra) each appear on three.
Certain native shrubs, such as southern bayberry (Morella cerifera), common yucca (Yucca filamentosa), sweet pepperbush (Clethra alnifolia), and inkberry (Ilex glabra), are fairly salt-tolerant, appearing on six to seven lists each. Yaupon (Ilex vomitoria), red and black chokeberry (Aronia arbutifolia and Aronia melanocarpa), and highbush blueberry (Vaccinium corymbosum) appear on three to four lists. Virginia creeper (Parthenocissus quinquefolia), a vine, is the only other woody plant that appears frequently on these lists.
Among the native grasses, sea oats (Uniola paniculata) which is native to coastal areas, switchgrass (Panicum virgatum), little bluestem (Schizachyrium scoparium), and pink muhly grass (Muhlenbergia capillaris) are considered to be salt-tolerant. Common rush (Juncus effusus) shows tolerance for salt spray in urban environments but not for constant, seaside exposure. While sedges, in general, are sensitive to salt concentrations, Gray’s sedge (Carex grayi) is reported by some sources to be suitable for roadside swales or rain gardens that may experience salty runoff.
Seaside goldenrod (Solidago sempervirens) is by far the most salt-tolerant perennial, followed by swamp rose-mallow (Hibiscus moscheutos), eastern prickly-pear (Opuntia humifusa), and New England aster (Symphyotrichum novae-angliae). Black-eyed Susan (Rudbeckia hirta), Virginia blue flag (Iris virginica), wild columbine (Aquilegia canadensis), and butterfly-weed (Asclepias tuberosa) each appear on three regional lists.
You can learn more about these salt-tolerant plants by following the links to fact sheets and see photos of plant features and landscape uses in the recorded presentation mentioned above, beginning at 0:18:30.
References
- Best Bets: Salt-Tolerant Native Plants, MGNV
- “Managing Salt Damage in Your Garden”, MGNV Master Gardener Virtual Classroom
- Trees and Shrubs That Tolerate Saline Soils, Salt Spray, and De-Icing Salts, VCE Publication 430-031
- “Understanding of Plant Salt Tolerance Mechanisms and Application to Molecular Breeding”, International Journal of Molecular Sciences, 2024, Volume 25, Issue 20
National Winter Salt Week – January 26 – 30 – From Arlington County
“Winter Salt Week is a national-scale event dedicated to raising awareness around salt pollution and reduction solutions. Partners come together to highlight challenges, showcase successes, and elevate the need for broader action around winter salt management.
On January 21 and 23 2026, join representatives from the D.C. Metro Region for two mini-webinar events to learn how you can take action around your community to stay safe and reduce salt impacts to the Potomac and other DC area water sources. From January 26-30, 2026, Winter Salt Week will hold numerous national webinar events as well as local events in the D.C., Maryland, and Virginia region.”
Register to attend the National Winter Salt Week webinars
- Freshwater Salinization: Causes, Consequences and Trends, Monday, January 26, 1:30-2pm ET
- Salt Wise Success Stories: Tuesday, January 27, 1:30-2pm ET
- Smart Salting Contracts: Wednesday, January 28, 1:30-2pm ET
- Engineering Solutions, Thursday, January 29, 1:30-2pm ET
- Advocating for Change, Friday, January 30, 12-1pm ET
- Salt Monitoring 101, Friday, January 30, 1-2pm ET