NRCS−Montana−Technical Note−Invasive Species−MT-30 1

United States Department of Agriculture

NATURAL RESOURCES CONSERVATION SERVICE

Invasive Species Technical Note No. MT-30

December 2010

 

Best Management Practices for Montana

Biology, Ecology, and Management of Russian Olive (Elaeagnus angustifolia L.) 

and Saltcedar (Tamarix ramosissima, T. chinensis, and their hybrids)

By

Jeff Combs, Biologist, NRCS, Bozeman, Montana 

I. Introduction: History/Identification/Threat for Russian Olive 

A. Russian Olive History: Russian olive (Elaeagnus angustifolia L.) is a member of the 

Oleaster family. Russian olive originated on the European Continent and ranged from 

southern Europe to western and central Asia (Little 1961). Russian olive was introduced 

to the United States in the early 1900’s. Tolerant to diverse site conditions, Russian 

olive has been planted as an ornamental (Little 1961), and used extensively in 

shelterbelts in the drier regions of the Great Plains and Rocky Mountains (Read 1958). 

In Montana, east of the Continental Divide, Russian olive trees have been used in 

shelterbelts, windbreaks, wildlife habitat, ornamentals and for wildlife habitat. Plants 

that have naturalized thrive along riparian corridors, irrigation delivery systems, 

pastures, saline affected areas and some wetland sites.

B. Russian Olive Identification: Russian olive is a large, thorny, perennial deciduous 

shrub or small tree (up to 40 feet). The leaves are alternate and simple, elliptical to 

lanceolate in shape, 1 to 3 inches long and 1⁄2-inch in width, scaly on the top and silvery 

and scaly on the bottom, dull green to gray in color. Stems may be thorny. The bark 

appears smooth and reddish brown to gray in younger trees and becomes unevenly rigid, 

wrinkled and graying in color as it matures. The fruit is berry-like, approximately 1⁄2-

inch in length, dry, mealy, sweet, and edible.

C. Russian Olive Threat: Russian olive infestations threaten native plant communities in

riparian areas and grasslands, as well as irrigated pastures and hay land. Russian olives 

have been identified along all of the watersheds in eastern Montana. Along riverine 

areas native cottonwood and willow species are being replaced by Russian olive through 

competition and succession. Russian olive grows relatively quickly and develops a 

dense canopy; preventing shade-intolerant native vegetation from establishing. Katz and 

Shafroth (2003) report that Russian olive constitutes a new functional guild; it can 

establish beneath the canopy of native riparian trees and can form self-replacing stands. 

In addition, there are selective pressures from mammals. Lesica and Miles (1999) 

observed that beavers select cottonwood and willow over Russian olive to forage on; 

providing Russian olive plants an additional competitive edge over native woody 

riparian vegetation. 
NRCS−Montana−Technical Note−Invasive Species−MT-30 2

II. Introduction: History/Identification/Threat for Saltcedar

A. Saltcedar History: Saltcedar (Tamarix ramosissima Ledeb, T. chinensis, Lour., and 

their hybrids) are members of the Tamarix family. Saltcedars are invasive deciduous 

shrubs or treelike shrubs. Native to eastern Turkey and Korea (Jacobs and Sing 2007), 

these species and their hybrids have evolved in conditions where winters are severe and 

frost-free growing seasons range from 60 to 120 days. Saltcedar populations were first 

reported in 1960 in Montana and now can be found along nearly all of eastern Montana’s 

rivers, lakes and reservoirs (Pearce and Smith 2003; and Jacobs and Sing 2007). Since 

the introduction of saltcedar in 1960, saltcedar has spread to Musselshell, Yellowstone 

(and its tributaries), Clark Fork, and the mid- to lower portions of the Missouri 

watersheds. Pearce and Smith (2003) also identified individual locations of saltcedar 

along the Milk River, Marias River, Canyon Ferry Reservoir and Flathead Lake.

B. Saltcedar Identification: Saltcedar stems are arching with the young bark a distinctly 

smooth, reddish-brown with light-colored leaf scars. Mature branches and stems 

become brownish-purple, ridged and furrowed (Jacobs and Sing 2007). The plants can 

grow up to 20 feet in height, with stems dying back to the growth collar during winter. 

Leaves are scale-like, small and overlapping; similar in appearance to cedar or juniper 

leaves. They are grey-green in the spring and turn a golden brown in the fall. The 

flowers are pink to white and small. They are clustered in showy compound catkin-like 

racemes. Flowers will bloom from May through September and infrequently into 

October. 

A mature saltcedar (i.e., 3-5 years old) will produce capsules containing thousands of 

very small seeds. Seeds are reported to be viable from 45 to 130 days depending on the 

seasonal and site-specific conditions. The seeds have a tuft of hair at the tip of the seed 

coat, which aids in dispersal. The principle dispersal mechanisms are wind and water, 

but seeds may also be spread by wildlife. 

C. Saltcedar Threat: Saltcedar and their hybrids are listed in the State of Montana as 

Priority 2B Noxious Weeds (Montana Noxious Weed List, January 2010). The various 

species of saltcedar are a significant threat to Montana’s riparian and sub-irrigated lands. 

Mature saltcedar plants will produce nearly half a million seeds during the growing 

season. Exposed riverbanks, shorelines, sandbars, receding wetlands leave bare, moist 

soil conditions that are ideal for saltcedar germination. These areas can have up to 800 

seedlings per square meter. However, many of these seedlings do not survive their first 

year. Saltcedar seedlings can have a mortality rate as high as 90%. Seedlings that 

establish above the line of disturbance along riverbanks and shorelines typically mature 

into seed-producing plants. 

Saltcedar has the ability to alter the soil chemistry and therefore affects the plant species 

that will grow in those areas. Saltcedar is deep-rooted and tolerant of saline soil 

conditions. Saltcedar uptakes salt from the soil and secrete these salts from glands 

located on the undersides of their leaves. The secreted salts can accumulate in the upper 

soil layer; changing the soil chemistry around the plants. This can create a saline 

condition in soil that can prevent some native plant species from establishing. 
NRCS−Montana−Technical Note−Invasive Species−MT-30 3

III. Integrated Pest Management (IPM) Control Method: Integrated Pest Management is the 

application of multiple management acts that are mutually supportive, and should include 

actions that cultivate competitive desirable plants and actions that suppress undesirable plant 

populations (i.e., weeds). The goals of IPM go beyond weed control including the reduction 

of weed management expense, and reducing herbicide applications. The key to successful 

IPM includes understanding the biology of the weed, understanding the ecology of the 

system, and careful and thorough planning. The general principles of IPM are prevention, 

early detection and small-scale population reduction, containment, and large-scale 

population reduction. Being diligent and persistent is necessary to successful treat and 

control Russian olive and saltcedar.

A. Prevention is guided on how Russian olive and saltcedar spread and their requirements 

for establishment:

1. Understand their life cycle requirements.

2. Understand their dispersal mechanisms and establishment requirements. 

3. Maintain competitive plant communities.

B. Early Detection and Small-Scale Population Reduction:

1. Persistent field surveys of likely risk areas such as receding shorelines and river 

banks, irrigation delivery infra-structure, and saline areas. 

2. Spot herbicide treatments.

C. Containment: 

1. Diligent monitoring.

2. Use herbicide/mechanical control on all known seed dispersing shrubs. 

3. Reducing ground disturbance activities.

D. Large-Scale Population Reduction is accomplished through the diligent implementation 

of the first three described above, and: 

Use bio-controls for saltcedar when permitted. Previously authorized bio-control 

permits for saltcedar have been terminated (APHIS 2010) pending restoration 

review/activities.

IV. Russian Olive – Saltcedar Treatments:

A. Basal Bark Application (Terrestrial Application): Most appropriate for plants with 

multiple small-diameter (i.e., less than 3” basal diameter) stems.

1. Chemical to be used: 

a. Triclopyr amine (Garlon 3A®; for use in areas with surface water present or near 

aquatic environments) 

b. Triclopyr ester (Remedy®, Garlon 4®, consult your local County Weed Control 

Supervisor and Extension Agent for other triclopyr ester products, follow label 

recommendations for low-volume basal bark treatment). 

2. Application rate: 25% to 33% solution. 
NRCS−Montana−Technical Note−Invasive Species−MT-30 4

3. Acceptable dates of application: Any time of year except when the bark is wet, 

frozen, or frost is on the stem. Fall is optimum because there is less foliage to 

intercept spray and non-target plants are dormant. Avoid application during rapid 

growth in the spring. 

4. Carrier used: Basal oil (preferred), diesel, kerosene, or methylated seed oil (MSO). 

An oil carrier must be used for the basal bark treatment to be effective.

5. Special application techniques: Read and follow label instructions for mixing 

herbicide in oil and for low-volume basal bark treatment. Add herbicide product to 

the required amount of oil in the spray tank or mixing tank and mix thoroughly. If 

mixture stands over four hours, re-agitation is necessary. Adjust nozzle for narrow 

cone-shaped spray, spray solution lightly but evenly from the root collar (ground) up 

to 18 inches thoroughly wetting all sides of every stem but not to the point of runoff. 

Old or rough bark requires more spray than smooth, young bark. Do not apply to 

wet, frosted, or frozen stems, or when snow or water prevents spraying to the ground 

line. 

B. Cut Stump Application (Terrestrial Application): Most appropriate for plants with 

large (i.e., greater than 3” basal diameter) stems and thick rough bark. 

1. Mechanical/physical removal: Use mowers, loppers, chainsaws, timber axe, 

bobcats fitted with cutting shears or sawing attachments. Use the appropriate-sized 

equipment based on the density and size of the Russian olive or saltcedar being 

treated. 

2. Chemicals to be used: 

a. Triclopyr amine (Garlon 3A®; for use in areas with surface water present or near 

aquatic environments), 

b. Triclopyr ester (Garlon 4®, Remedy®, consult your County Weed Control 

Supervisors and Extension Agent for other products, follow label 

recommendations for cut stump treatment).

3. Application rates: 

a. Triclopyr amine – 50% solution, 

b. Triclopyr ester – 25-30% solution (preferred). 

4. Acceptable dates of application: Any time of year as long as the herbicide does not 

freeze when applied and the tree is not frozen.

5. Carrier used: 

a. Triclopyr amine – water,

b. Triclopyr ester – basal oil (preferred), diesel, kerosene, methylated seed oil 

(MSO).

6. Special application techniques: Read and follow label instructions for mixing 

herbicide in carrier and for cut stump treatment. Cut stump close to ground level but 

leaving enough stump to be able to locate them and apply herbicide. However, in 

hay and pasture fields where driving wheeled vehicles is necessary consider cutting 

the stumps closer to the ground. Apply herbicide with a backpack sprayer using low 

pressure and a solid cone or flat-fan nozzle. Spray the root collar area, sides of the 

stump, and the outer portion of the cut surface including the cambium until 

thoroughly wet but not to the point of runoff. Spray as soon as possible after cutting 

stem. Stumps cut longer than one hour before herbicide application is made should 

be treated using the triclopyr ester in an oil carrier. Apply anytime except when 

snow or water prevents spraying to the ground line. 
NRCS−Montana−Technical Note−Invasive Species−MT-30 5

C. Burning, Cultivation, Grazing, Mowing and Hand Pulling: These treatments when 

used independently have not proven to be effective for controlling Russian olive or 

saltcedar. The plants have extensive root systems and ability to regenerate and develop 

new plant material from roots remaining in the soil material. This can be problematic 

since re-sprouts develop multiple stems resulting in a dense, thick plant that is difficult 

to treat with the chemical/mechanical treatments mentioned previously. However, when 

used in combination with herbicide treatments described previously, these methods may 

be incorporated into an Integrated Pest Management Plan for Russian olive and 

saltcedar.

D. Biological Controls: Effective biological controls have been found for all species of 

saltcedar occurring in Montana. The leaf beetle, Dirhabda elengata Brulle, is originally 

from China and Kazakhstan and has been successfully field tested in the southwestern 

states and federally permitted in 13 western States. Currently, the USDA (as of the date 

of the technical note) Animal and Plant Health Inspection Service (APHIS) has 

terminated previously issued permits and discontinued issuing new permits for Dirhabda

biological control releases. The reason for this decision was based on concerns 

regarding critical habitat of the federally-listed endangered southwestern willow 

flycatcher (Empidonax trailii extimus) and the biological control agent D. elengata

(including all species, subspecies, or ecotypes in the Dirhabda elengata complex). 

USDA APHIS will continue to survey and evaluate the biological control program, and 

assess the impact on saltcedar density and the re-establishment of native vegetation. 

Currently, there are no biological controls available to treat Russian olive or saltcedar 

(including saltcedar hybrids). 

V. Woody Debris Removal: 

A. Pile stems and burn: Stems and debris should be collected in piles and burned. This 

may take a year or more before the piles will be dry enough to burn. 

B. Chip the stems: Run stems through a shredder at the time of harvest and disperse the 

material across the treatment site.

C. Pellet the stems: Have the stems chipped and manufactured into pellets for wood 

burning heating units. 

VI. Noxious Weed Control Treatments: Noxious weed treatment in some areas will be as 

important as the treatment of Russian olive or saltcedar. Noxious weeds may establish, 

deposit seed and basically remain in a state of dormancy around and under Russian olive and 

saltcedar. Weedy species such as Canada thistle, houndstongue, kochia, leafy spurge, 

spotted knapweed, Russian knapweed, and toadflax may lie dormant for years in the shade 

of Russian olive and or saltcedar canopies. Once the canopy is removed these species may 

flourish, especially in the case of Russian olive. Russian olive fixes nitrogen in the soil. 

Annual and perennial weeds thrive in nitrogen rich soils, so when the Russian olive canopy 

is removed, weeds may become a significant management issue on these sites.

It is essential to evaluate the site and determine if noxious weeds need to be treated during 

and likely after the control treatments are initiated for Russian olive and saltcedar.
NRCS−Montana−Technical Note−Invasive Species−MT-30 6

VII. Monitoring: Monitoring should be conducted frequently and diligently throughout the 

subsequent growing seasons. Below are several suggestions for consideration: 

A. Thoroughly inspect field borders, exposed river banks, lake, pond or wetland shorelines, 

fence lines, areas of ground disturbance, irrigation infrastructure (i.e., irrigation delivery 

ditches, seeps, etc.), livestock trails, access roads, etc for signs of new growth and/or resprouts. 

B. New growth and re-sprouts can be hidden under previous years vegetation cover. 

C. Ensure that treated sites are inspected no later than two years following a completed 

control treatment.

D. Evaluate the existing vegetation community. 

1. Is the targeted plant community/composition desirable? 

2. Is there an abundance of weeds that will need treatment?

E. Diligently treat all re-sprouts and/or new growth. 

VIII. Post Treatment Vegetation Establishment:

A. See the attached Russian olive – saltcedar Post-Control Treatment Re-Vegetation 

Species List and Recommended Practice Standards Document. 

IX. Summary:

A. Successful invasive species management and long-term control of Russian olive and 

saltcedar depends on early identification/detection, treatment, monitoring, and 

commitment for the project. With technical and financial assistance from local, state, 

tribal, and federal agencies; landowners can make a significant contribution to the 

control of these invasive species. 
NRCS−Montana−Technical Note−Invasive Species−MT-30 7

Literature Cited:

Jacobs, J. and S. Sing. 2007. Biology and Management of Saltcedar (Tamarix ramosissima, T. 

chinensis, and T. ramosissima x T. chinensis hybrids). USDA-NRCS Invasive Species. 

Technical Note No. MT-13. 

http://www.mt.nrcs.usda.gov/technical/ecs/invasive/technotes/invasivetechnotemt13/. 12 p. 

Katz, G. L. and Shafroth. 2004. Biology, Ecology and Management of Elaeagnus angustiolia L. 

(Russian olive) in Western North America. Wetlands 23(4): 763-777. 

Lesica, P. and S. Miles. 1999. Russian olive invasion into cottonwood forests along a regulated 

river in north-central Montana. Can. J. Bot. 77: 1077-1083. 

Little, E.L. 1961. Sixty Trees from Foreign Lands. USDA. Forest Service Agricultural 

Handbook 212, Washington, D.C. 

Read, R. A. 1958. The Great Plains Shelterbelt in 1954. Great Plains Agricultural 

Council. University of Nebraska Experimental Station, Lincoln, NE, USA. Publication No. 

16. 

Pearce, C. M. and D. G. Smith. 2003. Saltcedar: Distribution, Abundance, and Dispersal 

Mechanisms, Northern Montana, USA. Wetlands 23(2): 215-228. 

Additional Reference

Stannard, M., D. Ogle, L.Holzworth, J. Scianna, and E. Sunleaf. April 2002. History, Biology, 

Ecology, Suppression and Revegetation of Russian-Olive Sites. USDA, NRCS, Plant 

Materials. Technical Note, MT-43.