Prepared by:

Curtis E. Swift, Ph.D., Area Extension Agent (Horticulture)
Colorado State University Extension
Tri River Area

An Introduction to Salts
Publications Available from Colorado State University

The Plant List

• Trees
  • Deciduous
  • Coniferous
• Shrubs
• Vines
• Flowers
• Grasses and other ground covers

References Used

Soluble salts can cause harm to plants if they are in high enough concentration in water or soil. This effect is mainly indirect by pulling moisture out of roots and reducing the uptake of water and nutrients to affected plants. Some salts can be toxic to root tissue. Tip and edge burn of leaves, slow growth, nutrient deficiencies, wilting and eventual death of the plant can occur if the salt level is excessive for the plant and the problem is not corrected. To avoid plant loss in salty sites, a soil test should be done to determine the soil salt level and plants selected based on their salt tolerance.

Soil testing laboratories will report the salinity (conductivity) of soil in decisiemens per meter (dS/m) (equivalent to the old measure of millimhos per centimeter). The salinity of irrigation water is typically reported in micromhos per centimeter (umhos/cm) or microsiemens per meter (uS/m) .

Conductivity is defined as the ability of a solution to conduct an electrical current, or the reciprocal of the solution's ability to resist the current. This current is conducted by electrically charged particles called ions, which are present in almost all solutions. Different solutions have different kinds and amounts of ions: distilled water has very few ions, and therefore a low conductivity, while sea water has a large number of ions, and a high conductivity. The greater the conductivity of the solution the higher the reading.

The following references on salts are available from the Colorado State University Publications on Line Site:

1. Salt-affected soils - an explanation of saline, sodic and saline-sodic soils and their treatment
2. Management of salt- and sodium-affected soils - covers problem diagnosis, reclamation treatments and prevention and control
3. Crop tolerance to soil salinity - provides some data on the salt tolerance of field, forage, vegetable and fruit crops
4. Irrigation water quality criteria - explains the four basic criteria for evaluating water quality for irrigation purposes - salinity and sodium hazard, toxic elements and bicarbonate concentration
5. Growing turf on salt-affected (alkali) sites - provides information on the salt tolerance of various cool-season grasses used for turf and provides information on which turf grasses to choose based on the salt level in the soil. How to reduce the salt level in the soil is also discussed.

To access these publications contact the Colorado State University Extension Web site. To read some of these publications you will need to download Acrobat Reader. A link to Acrobat Reader is provided from CSU's site. If you live in Colorado these publications are available from any CSU Extension office.

The following information was gleaned from various publications and personal experiences of nurseryman in Western Colorado's Tri River Area and is suggested as a guide when recommending trees, shrubs, vines and herbaceous plants for salty sites. Information regarding other temperate zone plants and their salt tolerance would be appreciated. Please send comments and additional references to Cuartis.Swift@colostate.edu .

High Tolerance - up to 8 mmhos(mS)
Acer plantanoides - Norway Maple
Aesculus hippocastanum Common Horsechestnut
Ailanthus altissima - Tree of Heaven
Amelanchier canadensis - Shadblow
Crataegus crus-galli - Cockspur Hawthorn
Elaeagnus angustifolia - Russian Olive - possibly up to 10 mmhos
Gleditsia triacanthos - Honeylocust
Quercus alba - White Oak
Quercus robur - English Oak
Quercus rubra - Red oak
Robinia pseudoacacia - Black Locust
Ptelea trifoliata - Wafer Ash

Moderately High Tolerance - up to 6 mmhos
Acer negundo - Box-elder
Acer ginnala - Amur maple
Betula lenta - Sweet Birch
Betula populifolia - Grey Birch
Betula alleghaniensis - Yellow Birch
Betula papyrifera - Paper Birch
Fraxinus americana - White Ash
Populus alba - White Poplar
Populus deltoides - Eastern Cottonwood
Populus grandidentata - Large-toothed Aspen
Populus nigra - Lombardy Poplar
Populus tremuloides - Trembling (Quaking) Aspen
Prunus padus - European Bird Cherry
Prunus serotina - Black Cherry
Prunus virginiana - Choke Cherry
Salix alba `Tristis' - Golden Weeping Willow
Salix alba `Vitellina' - Golden Willow
Salix nigra - Black Willow
Sophora japonica - Japanese Pagoda Tree
Ulmus pumila - Siberian Elm

Moderate Tolerance - up to 4 mmhos
Catalpa speciosa - Northern Catalpa
Celtis occidentalis - Hackberry
Celtis reticulata - Netleaf hackberry
Cercis occidentalis - Western Redbud
Fraxinus anomala - Singleleaf Ash
Fraxinus excelsior - European Ash
Fraxinus pennsylvanica - Green Ash
Ginkgo biloba - Maindenhair Tree
Koelreuteria paniculata - Goldenrain Tree
Maclura pomifera - Osage-Orange
Pyrus species - Pear
Ulmus americana - American Elm

Slight Tolerance - up to 2 mmhos
Quercus palustris - Pin Oak
Malus species and cultivars - Apple and Crabapple

Sensitive or Intolerant
Acer rubrum - Red Maple
Acer saccharinum - Silver Maple
Acer saccharum - Sugar Maple
Cercis canadensis - Eastern Redbud
Juglans nigra - Black Walnut
Plantanus acerifolia - London Plane
Sorbus aucuparia - European Mountain-Ash
Tilia americana - American linden
Tilia cordata - Littleleaf Linden

High Tolerance - up to 8 mmhos
Juniperus chinensis - Pfitzer juniper
Picea glauca ` densata' - Black Hills Spruce
Pinus mugo - Mugho Pine
Pinus nigra - Austrian Pine

Moderately High Tolerance - up to 6 mmhos
Pinus ponderosa - Ponderosa Pine
Pinus thunbergiana - Japanese Black Pine
Thuja occidentalis - American Arborvitae

Slight Tolerance - up to 2 mmhos
Picea albies - Norway Spruce
Pinus strobus - Eastern White Pine
Pinus sylvestris - Scot's Pine
Pseudotsuga menziesii - Douglas Fir
Taxus cuspidata - Japanese Yew

Sensitive or Intolerant
Abies balsamea - Balsam Fir
Pinus resinosa - Red or Norway Pine
Tsuga canadensis - Canadian Hemlock

Very High Tolerance - Up to 10 mmhos
Atriplex canescens - Fourwing Saltbush
Atriplex convertifolia - Shadscale Saltbush
Atriplex corrugata - Mat Saltbush
Atriplex nuttalli - Nuttall Saltbush
Atriplex nuttalli cuneata - Castle Valey Clover
Atriplex nuttalli gardneri - Gardner Saltbush
Baccharis emoryi - Emory Baccharis
Baccharis glutinosa - Seep-Willow
Ceratoides lanata - Common Winterfat
Chrysothamnus greenei - Greene Rabbitbrush
Chrysothamnus linifolius - Flaxleaf Rabbitbrush
Ephedra species - Mormon Teas
Ephedra torreyana - Torrey Ephedra
Kochia americana - Greenmolly Summercypruss
Sarcobatus vermiculatus - Black Greasewood
Tamarix pentandra - Five-Stamen Tamarix, Tamarisk

High Salt Tolerance - up to 8 mmhos
Caragana arborescens - Siberian Peashrub
Chrysothamnus albidus - Alkali Rabbitbrush
Cytisus scoparius - Scotch Broom
Elaeagnus commutata - Silverberry
Elaeagnus multiflora - Cherry Elaeagnus
Euonymous japonica - Spindle Tree
Halimodendron halodendron - Salt-tree
Hippophae rhamnoides - Sea Buckthorn
Juniperus chinensis - Pfitzer Juniper
Lonicera tatarica - Tararian honeysuckel
Rhamnus cathartica - Common Buckthorn
Rhus trilobata - Squawbush
Rhus typhina - Staghorn Sumac
Rhamnus frangula - Glossy Buckthorn
Shepherdia canadensia - Buffaloberry
Spiraea vanhouttei - Van Houtte Spirea
Symphoricarpuos albus - Snowberry
Syringa amurensis japonica - Japanese Tree Lilac
Syringa vulgaris - Common Lilac
Potentilla fruiticosa `Jackmanii' - Jackman's potentilla
Tamarix gallica - Manna Plant - Tamarisk

Moderately High Tolerance - up to 6 mmhos
Artemisia frigida - Fringed Sagewort
Artemisia spinescens - Bud Sagebrush
Artemisia tridentata - Basin Big Sagebrush
Buxus microphylla - Japanese Boxwood
Chrysothamnus nauseosus - Rubber Rabbitbrush
Chrysothamnus visci diflorus - Douglas Rabbitbrush
Ephedra nevadensis - Nevada Mormontea
Forsythia x intermedia - Showy Border Forsythia
Juniperus communis - Common Juniper
Philadelphus coronarius - Sweet Mockorange
Purshia glandulsa - Desert Bitterbrush
Pyracantha fortuneana - Pyracantha
Rhus glabra - Smooth Sumac
Rhus trilobata - Skunkbush Sumac - Three-leaf Sumac
Shepherdia rotundifolia - Roundleaf Buffaloberry
Spirea `Froebel's' - Froebel's spirea

Slight to Moderate - up to 4 mmhos
Artemisia cana - Silver Sagebrush
Berberis fremontii - Fremont Barberry
Robinia neo-mexicana - New Mexican Locust
Rosa woodsii - Wood's Rose
Salix exigua - Coyote Willow

Slight Tolerance - up to 2 mmhos
Chaenomeles speciosa - Flowering Quince
Ligustrum vulgare - Common Privet
Rosa rugosa - Rugosa Rose - may be slightly tolerant
Viburnum opulus - High Bush Cranberry

Sensitive or Intolerant
Cornus racemosa - Grey Dogwood
Cornus stolonifera - Red-osier dogwood
Rosa - Rose

High Tolerance - up to 8 mmhos
Lonicera tataricum `Zabelii' - Zabel's Honeysuckle
Parthenocissus quinquefolia - Virginia Creeper - Woodbine

Slight Tolerance - up to 4 mmhos
Lonicera japonica - Japanese Hall's Honeysuckle

High to Moderate - 6 to 8 mmhos
Aquilegia micrantha - Cliff Columbine
Machaeranthera xylorrhiza - Common Woody Aster
Psilostrophe bakerii - Paperflower
Stanley pinnata - Prince's Plume - a good indication that the soil is high in selenium

Moderate Salt Tolerance - 4 to 6 mmhos
Fallugia paradoxa - Common Apache
Oenothera caespitosa - Tufted Evening Primrose
Sphaeralcea coccinea - Scarlet Globemallow
Yucca elata Soaptree - Yucca
Yucca glauca - Small Soapweed

Slightly Tolerant - 2 to 4 mmhos
Argemone species - Prickly Poppies
Calochorutus species - Mariposa Lilly
Chyrsopsis villosa - Hairy Goldenaster
Gallardia pennatifida - Cutleaf Blanketflower
Mentzelia species - Blazing Stars
Physaria australus - Twinpod

High tolerance - 14 to 18 mmhos
Agropyron elongatum - Tall Wheatgrass
Agropyron smithii - Western Wheatgrass
Distichlis - Saltgrass
Elymus triticoides - Beardless wildrye
Lotus corniculatus = Birdsfoot trefoil - a legume
Puccinellia - alkaligrass
Sporobolus airoides - Alkali sacaton

Moderately High - 12 to 8 mmhos
Bromus marginatus - Mountain brome
Lolium perenne - Perennial ryegrass
Melilotus alba - White sweet clover
Melilotus officinalis - Yellow sweet clover
Trifolium fragiferum - Strawberry clover

Moderate - 8 to 4 mmhos
Agropyron cristatum - Crested Wheatgrass
Agropyron riparium - Streambank Wheatgrass
Agropyron trachycaulum - Slender Wheatgrass
Arrhenatherum elatium - Tall meadow oatgrass
Bromus inermis - Smooth brome
Buchloe dactyloides - Buffalograss
Dactylis glomerata - Orchardgrass
Elymus giganteus - Mammoth wildrye
Elymus junceus - Russian wildrye
Festuca arundinacea - Tall Fescue
Medicago sativa - Alfalfa
Phalaris arundinacea - Reed Canarygrass

Low salt Tolerance
Alopecurus pratensis - Meadow foxtail
Festuca rubra - Red fescue
Festuca elatior - Meadow fescue
Poa pratensis - Kentucky Bluegrass
Trifolium pratense - Red clover
Trifolium repens - White clover

Beckerson, D. W. ; Nancy Cain; Dr. Gerry Hofstra; D.P. Ormrod; and Patricia Cambell. 1980. - `A Guide to: Plant Sensitivity to Environmental Stress' Landscape Archtecture May. pp. 299 - 303
Farnham, D.S. 1979. Water Quality Affects Ornamental Plant Production. University of California, Leaflet 2995
Feucht, J.R. Trees and shrubs for High Alkalline and High Salt Conditions - Extension Service, Tri River Area, Colorado State University
Kearney, T. 1924. The Choice of Crops for alkali Lands. USDA, Farmers' Bulletin No. 446
Kvaalen, R. 1979. Roadside De-Icing salts and Ornamental Plants. Yard and Garden- Horticulture Department Extension Service, Purdue, Indiana
Miller, W. M. 1956 irrigatin Water Quality; Crop Tolerances. Agricultural Engineering. S.W.
Rich, A. E 1972.. Effects of salt on Eastern Highway Trees. American Nurseryman 135:36-39,
Sucoff, E. 1975. Effects of deicing salts on woody vegetation along Minnesota roads - Technical bulletin 303 - Foresty Service Minnesota Agricultural Station
Thornburg, A.A. 1982. Plant materials for Use on Surface-Mined Lands in Arid and Semiarid Regions. USDA- Soil Conservation Service
USDA, Some trees more tolerant to Salt - Grounds Maintenance, October 1983, Page 8
Weichuding, P.J. 1978. Minimizing salt Injury to Shade Trees - Minnesota Tree Lilne, Agricultural Extension Service, University of Minnesota Publication No 19

to the Soils of Western Colorado Home Page