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African rue (Peganum harmala)

ODA rating: A and T

African rue risk assessment
Noxious weed listing process
Oregon African Rue distribution
Other common names
wild rue, rue weed, and Syrian rue.

Click on image below to view larger photo
African rue plant  
African rue flower  
Images courtesy of Bonnie Rasmussen, Oregon Department of Agriculture.
African rue infestation  
If images are downloaded and used from the ODA web site please be sure to credit the photographer.

African rue is a multi-branched and bushy perennial. A member of the Caltrop family It is a succulent plant, with bright green alternating leaves that are smooth and finely divided with long, narrow segments. Plants grow 1.5 feet tall and 3-4 feet in diameter. Flowers are white with five individual petals and are present in spring to early fall. Fruit is a located in a leathery capsule 2-4 celled which contains 45-60 seeds. Seeds are angular, dark brown and have a distinctive smell. When crushed, the stems also have a disagreeable odor. The base of this plant is woody and roots can branch and reach 20 feet in depth. African rue prefers distributed environments such as roadsides, fields and rangelands in desert and semi-desert areas. It is often found in soils with high salinity and most parts of the plant contain allelopathic chemicals that reduce growth of other vegetation.

African rue contains at least four poisonous alkaloids. It is toxic to people and livestock. The seeds and fruit of the plant are the most toxic part with a lethal dose being 0.15 percent of an animal's body weight. Young leaves are less toxic then seeds with a lethal dose of about 1.0 percent of the animals's weight, while mature leaves are less toxic. Dry leaves are apparently nontoxic. This noxious weed is extremely drought tolerant and displays robust vegetative growth expanding into desert rangelands replacing native plants like saltbrush and grasses.  It has a competitive advantage over native plants as it germinates earlier in the spring.

African rue is native to the deserts of Africa and southern Asia.  There are known sites in New Mexico, Arizona, Texas, California, Oregon and Washington. Introduced from the Mediterranean region and Middle East. The plant was first recognized in the United States in 1920 near Deming New Mexico and has naturalized in parts of southwestern United States including Arizona, New Mexico, and parts of west Texas.  Dehulled seeds yield edible oil similar to cottonseed oil. Plants have been used medicinally and produce red dye in the Middle East.

Distribution in Oregon
The first documented site in Oregon was 1967 in Crook County. In 2008 African rue was identified in Harney County.
For a collection of spatial information on the distribution of this plant in Oregon go to Oregon WeedMapper.

Biological controls
Biological control agents are not used on "A" listed weeds in Oregon. This weed is being managed for eradication or containment.
Printable trifold African rue brochure (pdf)