Central Europe, the Mediterranean, northern Africa and western,
Annual bastard-cabbage is
an annual, many-branched, herbaceous plant that grows from 1 to 5 feet or
more in height and has a taproot that can become quite large. Leaves are
deep green, lobed and wrinkled, and sometimes have a reddish cast. The terminal
lobe is larger than the lateral lobes, especially on the basal leaves. Younger
leaves growing higher up on the plant are less lobed and more elongated.
Annual bastard-cabbage typically flowers from early spring into summer, bearing
clusters of small, showy yellow flowers at the tips of its branches, resembling
those of broccoli and cabbage. Annual bastard-cabbage can be identified more
easily and certainly by its unusually shaped fruit - a two-segmented seed
capsule, called a silique. The seed capsule is stalked, with a long beak
at the tip, and contains 1-2 seeds. The seeds are oval-shaped, dark brown,
smooth, and tiny (about 1/16-inch).
subspecies of this plant are recognized: R. rugosum ssp. rugosum and R.
rugosum ssp. orientale. Annual bastard cabbage is also known
as turnip-weed, common giant mustard, ball mustard, wild turnip, wild rape
and tall mustard-weed. It is designated a terrestrial noxious-weed seed in
the state of Texas.
is an early successional plant that develops a broad, robust mass of basal
leaves, which allows it to successfully outcompete native plant species.
In some places, it forms a monoculture (a vegetative cover of mostly one
species). Annual bastard-cabbage has long been established on agricultural
fields, roadsides, and disturbed lands and is becoming invasive in natural
areas such as open forests and along streams.
IN THE UNITED STATES
Annual bastard-cabbage is documented to occur
in sixteen states, from California to New England. Click here to
see a distribution map.
IN THE UNITED STATES
Annual bastard-cabbage grows mostly in open sites
on disturbed soils.
The history of introduction
of annual bastard-cabbage into the U.S. is uncertain. It appears to be spreading
through contaminated grass seed mixes or mulching materials. Because its
seeds are similar in size to those of wheat and rye, weed seed screens may
fail to remove it from grass seed mixes.
BIOLOGY & SPREAD
seeds germinate early in the growing season (late fall or early winter) and
quickly cover the ground with a blanket of leafy rosettes (circles of leaves
at ground level). These dense rosettes block sunlight from reaching seeds
and seedlings of native plants.
Manual removal of
the plant and its taproot, and disposal of seeds, is effective, though labor-intensive.
Research is now underway at the Lady Bird Johnson Wildflower Center to determine
if oversowing with native grasses and herbaceous groundcovers is effective
in controlling annual bastard-cabbage.
Chemical control of annual bastard-cabbage
may be difficult because of its ability to ability to attain resistance to
several selective herbicides. Research into effective herbicide control is
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.
For more information on
the management of annual bastard-cabbage, please contact:
- Steve Windhager, Ph. D.,
Lady Bird Johnson Wildflower Center, Austin, TX, stevew at wildflower.org
Simmons, Lady Bird Johnson Wildflower Center, Austin, TX, msimmons at wildflower.org
Karen Enyedy, Freelance Writer/Editor, Austin,
Jil M. Swearingen, National Park Service,
Mark Simmons and Dr. Steve Windhager,
Lady Bird Johnson Wildflower Center, Austin, TX
Mark Simmons, Lady Bird Johnson Wildflower Center,
Diggs, Jr., G. M., Lipscomb, B.L.,
and O'Kennon, R. J. Shinners and Mahler's Illustrated Flora of North Central
Texas. Fort Worth, TX: Botanical Research Institute; 1999; p. 476.
Hashem, A., Bowran, D., Piper, T.
and Dhammu, H. 2001. Resistance of wild radish (Raphanus raphanistrum)
to acetolacetate synthase-inhibiting herbicides in the Western Australia
wheat belt. Weed Technology 15:68-74.
Kartesz, J.T. and C.A. Meacham.
1999. Synthesis of the North American Flora. North Carolina Botanical Garden,
University of North Carolina at Chapel Hill. Chapel Hill, NC. [CD]
Lemke, David E. and Worthington,
Richard D. Brassica and Rapistrum (Brassicaceae) in Texas. The Southwestern
Naturalist; June, 1991: pp. 194-196.
Neiman, Bill*. Personal conversation
4/9/2000. *President, Native American Seed.
Rollins, Reed C. The Cruciferae
of Continental North America. Stanford, CA: Stanford University Press; 1993;
Swearingen, J. 2009. WeedUS Database of Plants Invading Natural Areas in the United States: Annual Bastard-Cabbage (Rapistrum rugosum). http://www.invasive.org/weedus/subject.html?sub=14105.
USDA, ARS, National Genetic Resources
Program. Germplasm Resources Information Network - (GRIN). [Online Database]
National Germplasm Resources Laboratory, Beltsville, Maryland. (http://www.ars-grin.gov/var/apache/cgi-bin/npgs/html)
USDA, NRCS. 2009. The PLANTS Database (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
Plant Conservation Alliance, Alien Plant Working Group.