African rue

Peganum harmala

Keys to Identification

The leaves are finely divided in long, narrow segments.
Flowers are white with five petals.

This information courtesy of the Colorado Natural Areas Program

Family: Zygophyllaceae (Caltrop)

Other Names: Syrian rue, Harmel shrub

USDA Code: PEHA

photo courtesy of La Plata County
Legal Status: Colorado Noxious Weed List A

Identification

Lifecycle: Perrenial

Growth form: Forb

Flower: Flowers are white, have five petals, and are borne along the stem in the leaf forks.

Seeds/Fruit: Seeds/Fruit: The fruit is a 2 to 4-celled leathery capsule that contains 45 - 60 seeds. Seeds are angular, dark brown with a distinctive smell. Soil seed bank viability period is currently unknown.

Leaves: Leaves are alternate, smooth, and finely divided with long narrow segments. When crushed there is a disagreeable odor

Stems: Mature plants are highly branched and grow 1.5 ft tall and 3-4 ft wide

Roots: Branching reaching to 20 feet deep

Seedling: More information is needed.

Impacts

Agricultural: African rue is toxic to livestock and can replace valuable forage subsequently reducing the productivity of pasture and rangeland.

Ecological: This plant is extremely drought tolerant, and it has expanded into desert rangelands replacing desirable native plants like saltbrush and grasses. It has a competitive advantage over native plants as it germinates earlier in the spring. Most parts of this plant contain allopathic chemicals that retard or prevent the growth of other vegetation.

Habitat and Distribution

General requirements: Adapted to relatively arid environments.

Distribution: Ppresent throughout New Mexico and is reported in Arizona, California, Idaho, Montana, Nevada, Texas, Oregon and Washington (USDA Plant Database).

Historical: Nnative of northern Africa, through the Middle East to Tibet in Asia. This plant was first recorded in the United States near Deming, New Mexico in 1928.

General requirements: Iis adapted to relatively arid environments.

Biology/Ecology

Mode of reproduction: Reproduces both vegetatively and by seeds.

Integrated Management Summary

This species is not yet established in Colorado, and should be a priority for immediate eradication if found. There is little or no information available on the control of African rue. Control efforts should focus on detecting infestations as early as possible and eliminating them. Remove plants before seed set, and dispose of properly.

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. 1996. African rue. Weeds of the West. Western Society of Weed Science, in cooperation with the Western United States Land Grant Universities Cooperative Extension Services, Newark CA. pg. 598.

CWMA