Keys to Identification:

Camelthorn is a member of the pea family.  Introduced from Asia, it grows in dry or moist soils and can be found along streams and canals.  Although it is not yet known to occur in Colorado, it has been found in New Mexico.

Camelthorn is a spiny perennial shrub that grows from 1-1/2 to 4 feet tall. The greenish stems have slender spines 1/4 to 1-3/4 inches long. Single leaves are wedge-shaped and alternate. Flowers are small, pea-like, pinkish purple to maroon, occurring on short spine-tipped branches on the upper portion of the plant.

Family: Fabaceae (Pea)

USDA Code: ALPS3 - Alhagi pseudoalhagi (Beib.) Desv.

ALMA12 - Alhagi maurorum Medik.

Legal Status: Colorado List A Noxious Weed

Identification

Lifecycle: Perennial

Growth form: Shrub. 1 1/2 - 4 feet tall

Flower: Pink

Seeds/Fruit: Reddish brown pods are constricted and break apart between the seeds. 5 to 8 seeds per pod.

Leaves: Simple, small, alternate, leathery. Upper surface is yellow-green with small red dots. Undersides are blue-green and covered with hairs.

Stems: Spiny

Roots: Deep woody roots. Rhizomes may spread up to 40 feet horizontally.

Seedling: Seeds need to be buried under shallow soil or animal manure.

IMPACTS

Agricultural: Invades hay fields and rangeland reducing forage quantity and quality.

Ecological: May be spread by animals. Forms dense patches which will out-compete native vegetation.

HABITAT AND DISTRIBUTION

General requirements: Prefers dry climates. Does best in areas of high fertility. Is deciduous in cold areas.

Distribution: Has been found in over 35 states.

Historical: Native to the Mediterranean region and to Asia. First found in North America around 1915. May have arrived as a contaminant in alfalfa seed.

Biology/Ecology

Life cycle: Perennial

Mode of reproduction: Reproduces mainly by spreading rhizomes. Each rhizome produces many new shoots that then send down deep woody roots. Also by seed.

Seed production: 700-4000 per plant under dry conditions. Lower under moist, shady conditions.

Seed bank: Seeds may last a number of years.

Dispersal: Animals. Spreading rhizomes. Wind and water.

Integrated Management Summary

Prevention and early detection are important in stopping this plant. There are no biological control agents available. Animals will graze but will spread the seed in their feces. Removal is not advisable since fragments of rhizomes will develop new plants. Chemical control has been used to eradicate it from parts of the western U.S.

REFERENCES

USDA, NRCS. 2005. The PLANTS Database, Version 3.5 (http://plants.usda.gov). Data compiled from various sources by Mark W. Skinner. National Plant Data Center, Baton Rouge, LA 70874-4490 USA

 

Whitson, T.D.(ed.), L.C. Burrill, S.A. Dewey, D.W. Cudney, B.E. Nelson, R.D. Lee, R. Parker. 9^th Edition 2000. Weeds of the West. Western Society of Weed Science, in cooperation with the Western United States Land Grant Universities Cooperative Extension Services, Newark CA.