Salt-Tolerant Trees and Shrubs

Tagged as: Salt-Tolerant Trees and Shrubs

Across the Midwest, the use of deicing salts (primarily sodium chloride) in winter to maintain safe roadways, sidewalks, and driveways is a common practice. Despite the benefits, deicing salt deposited on trees and shrubs can cause extensive damage. Deicing salt is dispersed from roads by plowing, meltwater runoff, splash, and aerial spray. Plants sensitive to salts may show injury early and can decline quickly after exposure. When air-borne deicing salt is deposited directly onto twigs, buds, or needles, salt draws moisture out of plant tissue, causing desiccation and burn. On evergreens, such as pines and firs, salt spray causes dieback starting at the tips of needles. On deciduous plants, the symptoms of salt damage become more evident during summer or during hot dry weather, when leaf margins show burn or scorch. Salt spray and excess soil salts can also cause branch dieback, stunted growth of stems and foliage, overall lack of vigor, and death. Turf grass along sidewalks and streets can be completely killed due to excess soil salt.

Symptoms Effects of Salt Injury

Air-borne Salt

• Plant damage caused by deposition of aerial salts is more widespread than that done by soil salts in the Midwest
• Injury caused by salt spray generally occurs on plants growing near highways and busy streets, where fast moving traffic causes salt dispersal onto nearby landscape plants
• Damage is most severe within 60 feet of the road and decreases with distance, but sensitive plants can show burn at distances of 1,000 feet or more from roadways
• On deciduous plants, salt spray can kill buds and twigs; new growth in spring appears as a cluster of twigs known as “witches’ broom
• On evergreens, salt spray causes browning or yellowing of needles and twig dieback, often on the roadside portion of the plant only; sensitive evergreens planted within 300 feet of roadways can sustain severe damage
• Branches protected by snow or other barriers are less likely to be injured

Soil Salt

• Plant injury due to soil salt can occur when salt-laden meltwater runs off or splashes onto the soil, and when salt is plowed and shoveled directly on the root zone of nearby plants
• Excessive soil salt accumulates in drainageways, depressions, or areas immediately adjacent to roadways where salt-laden runoff is channeled or splashed
• Concentrated quantities of sodium and chloride can damage plants by direct absorption into the roots, causing toxic effects or root dehydration
• Injury caused by excessive uptake of soil salt includes browning along leaf edges, stunted growth, or fewer and smaller leaves, flowers, and fruit
• Plants grown in poorly drained soils and those that are marginally hardy are more severely injured

Minimize the Injury of Salt Damage

• Avoid or minimize the use of salt around landscape plants
• Reduce the amount of salt used by mixing sand, sawdust, or cinders with salt before applying
• Wait to apply a deicer until after shoveling and plowing, and avoid shoveling salt-laden snow over the root zones of salt sensitive plants
• Alter drainage patterns to avoid accumulation of salt runoff near plants
• Protect low-growing plants susceptible to aerial salt damage by constructing temporary, physical barriers made of burlap or fencing
• Use salt-tolerant plants in highly exposed areas.
• Keep plants healthy by mulching to reduce water loss, and by irrigating to help move salts through the soil

Literature cited:

The inconsistency among various authorities in rating salt-tolerance of landscape plants makes it difficult for any one table to be thoroughly accurate. This compilation of salt tolerant plants was derived from the following sources:

Davidson, H. 1996. Tree and Shrub Tolerance to De-icing Salt Spray. Michigan State University
Extension Service Publication, HM-95

Delahaut, K.A., and E.R. Hasselkus.1996. Salt Injury to Landscape Plants. University of
Wisconsin Extension Service Publication, A2970.

Dirr, M.A. 1976. Selection of Trees for Tolerance to Salt Injury. Journal of Arboriculture
II:209-216.

Hootman R.G. and P.D. Kelsey. 1992. Woody Plants and Roadway Salt: An Urban Dilemma.
The Morton Arboretum Quarterly 28(3):44-48.

Kelsey, P.D. and R.G. Hootman. 1991 Case study: Deicing Salt Deposition on the Morton Arboretum. P. 253-283. In F.M. D’Itri (ed.) Deicing Chemicals and the Environment. Chelsea, MI

Sinclair, W.A., H.H> Lyon, and W.T. Johnson. 1987. Relative Tolerance of Plants to Salt.
Diseases of Trees and Shrubs, Ithaca, N.Y.p.454

Recommended Salt-Tolerant Landscape Plants
T = Plants with highest degree of salt tolerance. Use in the most exposed areas.
M = Plants with a moderate degree of salt tolerance. Use in low salt areas.
* = Plants tolerant of soil salt

Deciduous Trees
Scientific Name	Common Name	Zone	Aerial Salt Tolerance
Acer campestre	Hedge maple	5-8	M
Acer ginnala	Amur maple	2-8	M
Acer nigrum	Black maple	4-9	M
Acer pseudoplatanus	Sycamore maple	5-7	T
Acer saccharinum	Silver maple	3-9	M
Aesculus hippocastanum*	Horse-chestnut	4-7	T
Aesculus octandra	Yellow buckeye	4-8	M
Amelanchier x grandiflora	Apple serviceberry	4-9	T
Betula nigra	River birch	3-7	M
Carya cordiformis*	Bitternut hickory	4-9	T
Carya ovata	Shagbark hickory	4-8	T
Catalpa speciosa *	Northern catalpa	4-8	T
Celtis occidentalis*	Hackberry	2-9	M
Diospyros virginiana	Persimmon	4-9	M
Ginkgo biloba*	Ginkgo	3-8	M
Gleditsia triacanthos*	Honey locust	3-9	T
Gymnocladus dioicus*	Kentucky coffeetree	3-8	T
Juglans cinerea	Butternut	3-7	T
Juglans nigra*	Black walnut	4-9	T
Koelreuteria paniculata	Golden rain tree	5-8	M
Larix decidua	European larch	2-6	T
Larix laricina	American larch	2-5	T
Liquidambar styraciflua*	Sweet gum	5-9	T
Magnolia x soulangiana	Saucer magnolia	5-9	M
Malus (some cultivars) (x zumi ‘Calocarpa’, ‘Adams’, ‘Donald Wyman’, ‘Prairifire’)	Crabapple	5-7	M
Nyssa sylvatica*	Tupelo	4-9	M
Ostrya virginiana	Ironwood	3-9	M
Platanus occidentalis*	Sycamore	4-9	M
Prunus maackii	Amur chokecherry	3-6	M
Prunus virginiana*	Choke cherry	2-6	M
Pyrus calleryana	Callery pear	5-8	M
Quercus alba	White oak	3-9	T
Quercus bicolor*	Swamp white oak	4-8	M
Quercus ellipsoidalis*	Northern pin oak	4-6	M
Quercus imbricaria	Shingle oak	4-8	M
Quercus macrocarpa*	Bur oak	2-8	M
Quercus robur	English oak	4-8	T
Sassafras albidum	Sassafras	4-9	M
Syringa amurensis*	Japanese tree lilac	3-7	T
Syringa pekinensis*	Peking lilac	4-7	T
Taxodium distichum*	Bald-cypress	4-9	T
Ulmus ‘Regal’*	Regal elm	4-6	T

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