This
information courtesy of the Colorado Natural Areas Program
Family: Zygophyllaceae
(Caltrop)
Other Names:
Syrian rue, Harmel shrub
USDA Code: PEHA
Legal Status:
Colorado Noxious Weed List A
Identification
Growth form:
Perennial 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 feet tall and 3-4 feet in diameter.
Roots: Branching reaching to 20 feet in
depth
Seedling:
More information is needed.
SIMILAR SPECIES
Exotics: None known.
Natives: None known.
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:
African rue is
adapted to relatively arid environments.
Distribution: African rue is present
throughout New Mexico and is reported in Arizona, California,
Idaho, Montana, Nevada, Texas, Oregon and Washington (USDA
Plant Database).
Historical:
African rue is a native 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:
African rue is adapted to
relatively arid environments.
Biology/Ecology
Life cycle:
No information available.
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
Low-Impact, Selective Herbicide
Applications for Control of African Rue-USFS http://www.fs.fed.us/r3/publications/documents/ffh-african-rue.pdf
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
Creating an Integrated Weed
Management Plan http://parks.state.co.us/cnap/iwm_handbook/iwm_index.htm
Anonymous. 1999. Peganum Harmala.
Internet: 3/5/99. Available: http://www.lycaeum.org/drugs/Tryptamines/DMT/acacia/pegan.htm
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.
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photo
courtesy of La Plata County