By Vickie Wallace and Alyssa Siegel-Miles, UConn Extension

Salinity in soils can be a chronic problem for landscapes on school properties. Salt can infiltrate the landscape naturally from tidal flooding in coastal areas or from the repeated use of deicing salts along roadsides and in parking lots.

De-icing products are used on school property to keep roads and sidewalks clear for students and parents to safely reach school property. Anti-icers (usually in liquid form) are applied before a storm to prevent the bonding of ice and roadways when precipitation is expected to accumulate. De-icers (usually in solid form) break existing bonds between ice and the pavement. Rock salt (primarily sodium chloride) is the most commonly used de-icer, due to its effectiveness, availability, and relatively low cost. The salt dissolves in water to form a brine that has a freezing point lower than water. The brine melts the ice and helps to prevent the formation of more ice as temperatures drop.

DAMAGE TO SOIL AND PLANTS

Excessive salt causes significant damage to the environment. Due to the repeated application of deicing products through the winter, salt may accumulate in the soil. It percolates down through the soil from melting, salt-packed snow or it is dispersed from roads by plowing, runoff, splash and aerial spray. The quality of water bodies can also be adversely affected by road salt runoff into lakes, ponds, rivers and wetlands.

Accumulated sodium destroys soil structure and porosity, raises soil pH, and reduces the capacity of water infiltration. The cumulative result is increased soil compaction, soil erosion and water runoff. Salt is highly absorbent and binds tightly with water; when fresh water plants are exposed to salt, it creates an imbalance within the plant. This prevents plant roots from taking in water, or even draws water out of the roots, creating an environment of extreme water stress, even when water is abundantly available.

Sodium chloride also interferes with critical plant processes, including photosynthesis, respiration and transpiration. It creates an impediment to plant nutrient uptake, particularly with magnesium and potassium, making them unavailable to the plant.

All plant species have different levels of tolerance to salt. Plants can absorb salt directly from their roots or from salt residue on their surfaces, such as stems, buds, or leaves. A plant’s degree of tolerance to excessive salts in the soil may be different from its tolerance of salt residue on the plant’s surface. While symptoms of salt spray injury appear quickly, soil salt injury is slow to develop and may progress over several years. The degree of salt injury can be influenced by the plant’s genetics, type of exposure (aerial spray or soil), severity of exposure, climate, and time of year.

For most plants, too much salt causes visible damage, such as stunted growth, lack of overall vigor, and over time, death. When chlorine in salt water gets taken up by the plant it tends to accumulate at the edges of leaves and tips of stems. The result is edge and tip burn on leaves, and dead tips on stems. In general, young, tender buds in late winter and early spring are more susceptible to salt spray injury as plants break dormancy. Turfgrasses also are subject to salt injury from deicing salts or flooding during coastal storms. Browning of leaf and crown tissue can be severe.

“Shedding” of leaves is one of the only means that deciduous plants have to excrete salt from their tissues. Evergreen plants tend to suffer damage from concentrated salt more easily than deciduous plants since they do not drop their leaves on a yearly basis.

Salt damage can be observed as and can include:

• root and tissue dehydration.
• delay in leaf budbreak and flowering.
• stunted foliage and buds.
• reduced shoot growth.
• crown thinning and tufting of foliage at branch tips.
• premature fall coloration and defoliation of deciduous plants.
• browning/yellowing of evergreen needles (such as pine and spruce) and tip die-back of the needles.
• dead buds, twigs and scorched leaf margins on deciduous plants, which become more evident during the hot, dry summer weather.
• clusters of new shoots (witches’ brooms), that sprout where branch tips die back on deciduous plants.
• plant injury that is most severe on the side of the plant that faces the shoreline or on outer portions of dense plants.

Once a plant’s health is compromised by exposure to excessive salt, the plant will be stressed, weakened, and more susceptible to future damage from diseases and insects. Additionally, loss of plant vigor and die back exposes space for increased weed encroachment. The long-term impact of the damage depends on the amount of salt that permeates the landscape bed, as well as the soil texture and moisture level before infiltration.

Keep in mind that symptoms of salt injury may resemble those caused by other adverse environmental factors, particularly drought or air pollution. If salt injury is suspected, foliar analysis or soil tests can confirm the diagnosis. Contact your county extension office for specific instructions and information on this service.

Also, plants do not tolerate broken branches and often become disfigured when in beds that are covered and weighed down in large piles of snow all winter. If this is a concern, consider using perennials or shrubs that can be severely pruned without ill effects if branches are broken, such as Rhus aromatica ‘Gro-Low’ (fragrant sumac).

Some plants commonly used at schools that are especially sensitive to salt injury include:

·       barberry	·       crabapple	·       hemlock	·       roses
·       boxwood	·       eastern redbud	·       privet	·       viburnum
·       burning bush	·       European beech	·       Red maple	·       White pine

RECOMMENDATIONS TO REDUCE SALT DAMAGE IN THE SCHOOL LANDSCAPE

• Choose plants that have moderate to high salt tolerance anywhere near roads, sidewalks, or parking lots.
• Design the landscape so that salt sensitive plants are at least 60-100 feet from highways and 30-40 feet from streets, sidewalks and parking lots when salt runoff into soil is common.
• Use mulch to minimize water loss.
• Where possible, improve soil structure and drainage to more easily move salt through the Plants tend to be more salt tolerant in sandy, well-drained soil than in heavy clay soils.
• Application of gypsum to heavy clay soils that are high in salt will displace the sodium ion with calcium, improving both aeration and drainage. (Do not apply lime, which changes the acidity level of the soil, while gypsum does not.)
• Plant landscape material in raised, mounded beds (berms) to reduce the potential of salt in runoff water from moving into planted areas.
• Erect a physical barrier, such as snow fencing, or cover plants with burlap or landscape fabric to protect sensitive plants from excessive aerial spray and residue.
• Plant a screen or windbreak of dense, salt-tolerant plants between the roadways and desirable landscape plants.
• Avoid or minimize the use of deicing salts around landscape beds when possible.
• Avoid shoveling or plowing salt-contaminated snow onto plants.
• In spring, if irrigation is an option, flush the soil thoroughly with water (at least 6 inches) to help move salts through the soil.

• Wait to apply a deicer until after shoveling and In late winter and early spring, as plants are coming out of dormancy, avoid application of salt.
• Design beds away from sidewalks and parking lots so they are not in range of deicers and large piles of snow.
• Consider alternative deicing products containing potassium chloride and calcium chloride to melt snow when possible; or reduce the amount of salt used by mixing it with sand, sawdust or cinders before applying.
• Alter drainage patterns to direct water runoff away from landscape beds.
• Commercial anti-desiccant products have not proven effective in preventing salt spray injury.

SALT TOLERANT PLANTS

Plants that are tolerant of salt grow as well in saline soils as they do under normal conditions. Plant species with waxy foliage or scaled, protected buds are generally more tolerant of salt spray.

All of the plants on this list can be readily found in the trade and grow well in Connecticut. While most have only a medium tolerance to salt, that is sufficient for most spots in school and home landscapes that have salt issues from de-icers. Some highly salt tolerant species were not included because they are not easily found in local nurseries, or have other drawbacks, such as thorns, pest or disease issues, or just aren’t easy to grow in a landscape setting.

H = High salt tolerance
M = Medium salt tolerance
FS = Full Sun
PS = Part Shade

Woody Species	Salt Toler- ance	Height	Width	Flower Color	Flowering Time	Light	Native?	Attributes/Maintenance
Bayberry (Morella pensylvanica)	H	5-10’	5-10’	yellow- green	May	FS/PS	Yes	Syn. Myrica pensylvanica. Tolerates drought, erosion, wet soils. Roots form suckers to colonize an area. Best in groups or massed. Foliage fragrant; fruit showy – attracts birds, provides winter interest. Deer tolerant.
Blueberry, highbush (Vaccinium corymbosum)	M	6-12’	8-12’	white	Spring	FS/PS	Yes	Native to swamps but does well in dry, acidic, poor and sandy soils. Use mulch. Edible fruit.
Honey-locust (Gleditsia triacanthos f. inermis)	M	30-70’	25-40’	green	May-June	FS	Yes	Good street/parking lot tree. Tolerant of drought, deer, air pollution, clay soil. F. inermis is a thornless and nearly seedpod-free variety.

Serviceberry, downy (Amelanchier arborea)	M	15-25′	15-25′	white	March-April	FS/PS	Yes	Root suckers can be removed to produce a more tree like form, otherwise will become shrubby. Attractive fall color, fragrant flower; edible red berries attract birds. Moderate deer resistance.
Sumac, fragrant (Rhus aromatica ‘Gro-Low’)	M	1.5-2’	5-8’	yellow	Spring	FS/PS	Yes	If salt injury or die back, just cut the affected part down to 6″ and it will regrow. Deer resistant. Showy red fruit in fall; fast spreader.
Summersweet (Clethra alnifolia)	M	4-8’	4-6’	white, pink	Summer	FS/PS	Yes	Prefers part shade and moist, acidic soil supplemented with organic matter. Moderate deer resistance. Fragrant flowers; maroon fall color. Flowers attract butterflies and bees.
Sweetfern (Comptonia peregrina)	M	2-5′	4-8′	yellow (insignif icant)	April-May	FS/PS	Yes	Does well in dry, infertile soils; difficult to transplant, best when container grown. Deer resistant. Good for naturalizing and embankments. Foliage fragrant.
Winterberry (Ilex verticillata)	M	6-10’	6-10’	green- white	June-July	FS/PS	Yes	Not drought tolerant. Prefers moist, acid soils with compost. Tolerates heavy pruning – fruits on new wood. Male and female separate plants – both needed for showy red fruit production. Moderate deer resistance.

Herbaceous Species	Salt Toler- ance	Height	Width	Flower Color	Flowering Time	Light	Native?	Attributes/Maintenance
Bluestem, little (Schizachyrium scoparium)	M	2-4’	1.5-2’	purple- bronze	August- February	FS	Yes	Cut grass to the ground in late winter to early spring. Deer resistant. Bronze-orange fall foliage color.
Candytuft (Iberis sempervirens ‘Snowflake’)	M	12”	18-24”	white	May	FS	Yes	Evergreen, slow spreader. This cultivar is more dense and compact than the original species. Moderate deer resistance.
Columbine (Aquilegia spp.)	M-H	12-15”	12-15”	many	Spring	PS	Some Yes	Prefers moist, average to rich soils. Moderate deer resistance. Water well during periods of drought. Leaf miners only significant pest. If seen, simply cut foliage to ground and discard.
Joe Pye weed (Eutrochium purpureum)	M	5-7’	2-4’	mauve pink	July- September	FS	Yes	Syn. Eupatorium purpureum. Prefers moist soils that do not dry out. Cut plants to ground in late winter. Attracts butterflies. Several improved cultivars available – ‘Gateway’ or E. dubium ‘Little Joe’.

Pinks, cheddar (Dianthus sp.)	M-H	6-12”	12-15”	pink, white, red	Spring, Summer	FS	No	Drought tolerant; many cultivars. Makes a good ground cover or front of border plant. Moderate deer resistance.
Stonecrop (Sedum ‘Autumn Joy’)	M	2’	2’	pink	August- November	FS	No	Drought tolerant. Divide sedum every 3-4 years to maintain its compact growth habit. Older plants tend to split in the center if they have not been divided. Pinch back by half in early summer to help prevent splitting. Attracts butterflies.
Switchgrass (Panicum virgatum ‘Cape Breeze’)	M	24-30”	20-24”	amber	Late Summer	FS	Yes	Compact grass stays green through fall. Deer resistant. Attractive amber seedheads.
Yarrow (Achillea millefolium ‘Sunny Seduction’)	M	1.5- 2.5’	1-2’	yellow	June- September	FS	Yes	Drought tolerant. Fragrant flowers attract butterflies. Deer resistant.

REFERENCES:

Casagrande, R. A. (2016). Sustainable Trees and Shrubs for Southern New England. U of Rhode Island and U of Massachusetts Cooperative Extension Services. Print.

UConn. (2016). Coastal Landscaping Guide for Long Island Sound. Coastal Adaptation Tools | Adapt CT

Gould, A. (2013). Impact of Road Salt on Adjacent Vegetation. Plant Pest Advisory. Rutgers Cooperative Extension. http://plant-pest- advisory.rutgers.edu/impact-of-road-salt-on-adjacent-vegetation/

Leopold, D. J. (2005). Native Plants of the Northeast: A Guide for Gardening & Conservation. Native plants of the Northeast : a guide for gardening & conservation

Mitchell, J. (2025). 11 Salt-Tolerant Plants for Coastal and Road-Salt Areas. Garden Tabs https://gardentabs.com/salt-tolerant-plants-coastal-road-salt-area/

Home | Center for Land Use Education and Research

Missouri Botanical Garden. (2025). http://www.missouribotanicalgarden.org

Eco Beneficial. (2025.)  Chicago Botanic Garden Report: Joe-Pye Weeds & Their Relatives

Department of Water Regulating and Discharges

Wisconsin Lake County of Dane (2025).  Management | Land and Water Resources Department

Rutgers University. (2025). Plant & Pest Advisory — Rutgers Cooperative Extension

College of the Environment and Life Sciences. (2008). RI Coastal Resources Management Council. Coastal Buffer Planting Guide