NATIVE
RANGE
Eurasia and Africa
DESCRIPTION
Most saltcedars,
or tamarisks, are deciduous shrubs or small trees growing to 12-15 feet
in height and forming dense thickets. Tamarix aphylla is an evergreen
tree that can grow to 50 feet tall and tends to flower during the winter.
Saltcedars are characterized by slender branches and gray-green foliage.
The bark of young branches is smooth and reddish-brown. As the plants age,
the bark becomes brownish-purple, ridged and furrowed. Leaves are scale-like,
about 1/16 inch long and overlap each other along the stem. They are often
encrusted with salt secretions. From March to September, large numbers of
pink to white flowers appear in dense masses on 2-inch long spikes at branch
tips.
ECOLOGICAL THREAT
Saltcedars
are fire-adapted species and have long tap roots that allow them to intercept
deep water tables and interfere with natural aquatic systems. Saltcedar disrupts
the structure and stability of native plant communities and degrades native
wildlife habitat by outcompeting and replacing native plant species, monopolizing
limited sources of moisture, and increasing the frequency, intensity and
effect of fires and floods. Although it provides some shelter, the foliage
and flowers of saltcedar provide little food value for native wildlife species
that depend on nutrient-rich native plant resources.
DISTRIBUTION
IN THE UNITED STATES
Saltcedar occurs in the intermountain region
of the western United States, throughout the Great Basin, and California
and Texas.
HABITAT IN THE UNITED STATES
Saltcedar
establishes in disturbed and undisturbed streams, waterways, bottomlands,
banks and drainage washes of natural or artificial waterbodies, moist rangelands
and pastures, and other areas where seedlings can be exposed to extended
periods of saturated soil for establishment. Saltcedar can grow on highly
saline soils containing up to 15,000 ppm soluble salt and can tolerate alkali
conditions.
BACKGROUND
Saltcedar
was introduced to the western U.S. as an ornamental shrub in the early 1800s.
BIOLOGY & SPREAD
Saltcedar
spreads vegetatively, by adventitious roots or submerged stems, and sexually.
Each flower can produce thousands of tiny (1/25-inch diameter) seeds that
are contained in a small capsule usually adorned with a tuft of hair that
aids in wind dispersal. Seeds can also be dispersed by water. Seedlings require
extended periods of soil saturation for establishment.
MANAGEMENT OPTIONS
Management
of saltcedar requires a long term commitment to maintain at low levels and
prevent reinfestation. A variety of methods have been used in the management
of saltcedar, including mechanical, chemical and biological. The most effective
management probably involves a combination of these. Mechanical techniques
include hand-pulling, digging, root-cutting, use of weed eaters, axes, machetes,
bulldozers, fire and flooding. Removal by hand is generally recommended for
small infestations of saplings under 1-inch diameter. Root-cutting and bulldozing
may be effective but are costly, labor intensive and may cause extensive
damage to soils and lead to resprouting. Fire has been used with some success,
but because saltcedars are fire-adapted, they readily resprout after fire.
Flooding can be used to control salt cedar if root crowns remain submerged
for at least three months.
Chemical
For
extensive infestations of saltcedar, chemical control has been shown to be
the most effective method. Cautious use of herbicides aids in restoration
of saltcedar infested sites by allowing repopulation by native plant species.
Systemic herbicides (e.g., those that kill the plant from the root up) are
recommended for saltcedar management and application methods include foliar
sprays, cut stump treatments, basal bark treatments, and aerial sprays. Because
tamarisk usually grows in or adjacent to streams, wetlands and other waterways,
it is important to use products registered for aquatic application.
Biological
Fifteen insects
are being investigated as potential biological control agents for saltcedar.
Two of these, a mealybug
(Trabutina mannipara) and a leaf beetle (Diorhabda elongata),
have preliminary approval for release. Five others are being tested within
the United States and an additional eight species are under study overseas.
Final approval for release of the mealybug and the leaf beetle is pending
resolution of concerns regarding their potential impact to the southwestern
subspecies of the willow flycatcher (Empidonax trailii extimus), a
federally endangered bird. In parts of its range where native willows, its
natural nest trees, have been replaced by saltcedar, the willow flycatcher
now utilizes it for this purpose. Concern is over the possibility that, due
to the environmental damage caused by tamarisk, native plant species may
not be able to replace it if the biological control agents succeed in eliminating
it.
USE PESTICIDES WISELY: ALWAYS READ THE ENTIRE PESTICIDE LABEL CAREFULLY, FOLLOW ALL MIXING AND APPLICATION INSTRUCTIONS AND WEAR ALL RECOMMENDED PERSONAL PROTECTIVE GEAR AND CLOTHING. CONTACT YOUR STATE DEPARTMENT OF AGRICULTURE FOR ANY ADDITIONAL PESTICIDE USE REQUIREMENTS, RESTRICTIONS OR RECOMMENDATIONS.
NOTICE: MENTION OF PESTICIDE PRODUCTS ON THIS WEB SITE DOES NOT CONSTITUTE ENDORSEMENT OF ANY MATERIAL.
CONTACTS
For more information on
the management of saltcedar, please contact:
- Curt Deuser, U.S. National
Park Service, Lake Mead National Recreation Area
curt_deuser at nps.gov
OTHER LINKS
AUTHORS
Rose-Marie Muzika, U.S. Forest
Service, Morgantown, WV
Jil M. Swearingen,
National Park Service, Washington, DC
PHOTOGRAPHS
Jil M. Searingen, National
Park Service, Washington, DC (first photo)
Forest & Kim Starr, US Geological
Survey, HI
REFERENCES
Baum, B.R. 1978. The genus Tamarix.
The Israel Academy of Sciences and Humanities, Jerusalem.
Carman, J.G. and J.D. Brotherson.
1982. Comparisons of sites infested and not infested with saltcedar and Russian
olive. Weed Science 30:360-364.
DeLoach, C.J., M.J. Pitcairn,
and D. Woods. 1996. Biological control of saltcedar in Southern California.
In: Joe DiTomaso and Carl E. Bell, eds., Proceedings of the Saltcedar Management
Workshop, Rancho Mirage, California, pp. 30-31.
Howe, W.H. and F.L. Knopf. 1991.
On the imminent decline of Rio Grande cottonwoods in central New Mexico.
Southwestern Naturalist 36(2):218-224.
Hudson, Laura E. 1999. Climatic
and hydrologic effects on the establishment of Tamarix ramosissima in
the cold desert of northern Wyoming (Bighorn Lake). M.S. Thesis, University
of Montana, Missoula.
Jackson, N.E. 1996. Chemical
control of saltcedar (Tamarix ramosissima). In: Joe DiTomaso and Carl
E. Bell, eds., Proceedings of the Saltcedar Management Workshop, Rancho Mirage,
California, pp. 21-27.
The Nature Conservancy. Tamarisk:
Element Stewardship Abstract. In: Wildland Weeds Management & Research
Program, Weeds on the Web.
Plant Conservation
Alliance, Alien Plant Working Group.
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