California Invasive Plant Council

Brassica tournefortii

Common names: Sahara mustard; Morrocan mustard; Asian mustard

Brassica tournefortii (Saharan mustard or African mustard) is a winter annual (family Brassicaceae) found in deserts, desert dunes, and coastal scrub, including the San Joaquin Valley, Sonoran and Mojave Deserts, and southwestern region of California. Saharan mustard readily invades newly burned areas, and is known to increase fire frequency and fuel load. Increased fire frequency can cause scrub habitats to convert to grasslands because the native shrubs are not adapted to recurrent fires. The high biomass of Saharan mustard, along with frequent fires, may deplete soils of important nutrients, making native habitat recovery more difficult.

Cal-IPC Rating: High?

Explanation of Cal-IPC ratings

• High – These species have severe ecological impacts on physical processes, plant and animal communities, and vegetation structure. Their reproductive biology and other attributes are conducive to moderate to high rates of dispersal and establishment. Most are widely distributed ecologically.
• Moderate – These species have substantial and apparent-but generally not severe-ecological impacts on physical processes, plant and animal communities, and vegetation structure. Their reproductive biology and other attributes are conducive to moderate to high rates of dispersal, though establishment is generally dependent upon ecological disturbance. Ecological amplitude and distribution may range from limited to widespread.
• Limited – These species are invasive but their ecological impacts are minor on a statewide level or there was not enough information to justify a higher score. Their reproductive biology and other attributes result in low to moderate rates of invasiveness. Ecological amplitude and distribution are generally limited, but these species may be locally persistent and problematic.
• Alert – An Alert is listed on species with High or Moderate impacts that have limited distribution in California, but may have the potential to spread much further.
• Watch – These species have been assessed as posing a high risk of becoming invasive in the future in California.

CDFA Rating: C?

Explanation of CDFA ratings

• A – A pest of known economic or environmental detriment and is either not known to be established in California or it is present in a limited distribution that allows for the possibility of eradication or successful containment.
• B – A pest of known economic or environmental detriment and, if present in California, it is of limited distribution.
• C – A pest of known economic or environmental detriment and, if present in California, it is usually widespread.
• D – An organism known to be of little or no economic or environmental detriment, to have an extremely low likelihood of weediness, or is known to be a parasite or predator.
• Q – An organism or disorder suspected to be of economic or environmental detriment, but whose status is uncertain because of incomplete identification or inadequate information.
• * – An asterisk next to the rating indicates that a plant is included in the CCR Section 4500 list of California State Noxious Weeds.
• -* – This plant is included in the CCR Section 4500 list of California State Noxious Weeds, but is otherwise not rated.

More details

Assessment(s)

Plant Assessment Form - Information gathered by Cal-IPC on the impacts, rate of spread, and distribution of invasive plants in California. Does not include management information.

Species ID Card

Invasive Species ID Card - To support field identification of early detection species, Cal-IPC has designed a set of Species ID cards that can be downloaded, printed double-sided, and trimmed to size.

Weed Management Notes

• Management Notes - Information on management techniques and effectiveness from the University of California Cooperative Extension’s Weed Research & Information Center.

Cal-IPC Newsletter Articles

• Do solar panels mean sunny times for Saharan mustard?. Tanner, Karen E.; Parker, Ingrid M.; Haji, Sophia; Moore-O'Leary, Kara A.; Hernandez, Rebecca R.. Vol 28, Issue 3
• New insights for managing Sahara mustard. Max Li., Yue. Vol 24, Issue 1
• Taking to the air to locate, prioritize and treat effectively. Burger, Jutta C.. Vol 21, Issue 2
• Symposium at the “Gateway to the Sequoias”. editor. Vol 17, Issue 3
• Invasive plants research at UC Riverside. Holt, Jodie S.. Vol 13, Issue 2
• Ecology and management of alien annual plants in the California desert. Brooks, Matt; Berry, Kristin. Vol 07, Issue 3

Cal-IPC Symposium Presentations

Presentations are linked where available. Where a presentation is not available, find more information by reading the abstract in the Cal-IPC Symposia Archive.

• Response of Mojave Desert native perennials to inoculum from invasive and native annuals. Hernandez, Mayra; Parra, Olivia; Valliere, Justin (2023)
• Slaying the dragon: How Irvine Ranch Conservancy volunteers achieved management success in significantly reducing Sahara mustard (Brassica tournefortii) on a site in Orange County, California. Wilson, David (2023)
• Vegetation types at risk from Sahara mustard invasion: Using Maxent to inform early detection and conservation targets with climate change. Sweet, Lynn (2019)
• Hand-removal method impacts on labor effort, Sahara mustard and native species: to bag or not to bag? Sweet, Lynn; Prado, Jennifer; Barrows, Cameron (2018)
• Recent research on invasive weeds at the European Biological Control Laboratory (EBCL). Smith, Lincoln; Bon, Marie-Claude; Desurmont, Gaylord; Kashefi, Javid; Sforza, René; Tannières, Mélanie; Cristofaro, Massimo; Marini, Francesca; Goolsby, John; Rector, Brian; Vidovic, Biljana; Winkler, Daniel; Moran, Patrick (2018)
• Temperature-dependent influence of fungi on seed mortality suggests difference in seed bank persistence of Sahara mustard between California and Arizona. Li, Max (2018)
• The U.S. Marine Corps versus the Sahara mustard. Malusa, Jim (2018)
• Effects of renewable energy development on demography of Brassica tournefortii. Tanner, Karen (2017)
• Biocontrol of Sahara mustard: An update on exploration in the native range. Sforza, Rene (2016)
• Using population genomics to uncover the rapid colonization of Sahara mustard (Brassica tournefortii) in the United States. Winkler, Daniel E. (2016)
• Sahara mustard: from here to gone. McDonald, Christopher (2013)
• Effects of Sahara Mustard, Brassica tournefortii, on the biodiversity of a desert landscape. Murphy, Michelle; Barrows, Cameron W. (2010)
• Evening the odds: Evaluating the combined effects of nitrogen fertilization and exotic annual removal on native annual forbs in the Colorado Desert. Schneider, Heather; Allen, Edith (2009)
• Phenology of Brassica tournefortii in comparison to B. nigra, B. geniculata, and native Mojave Desert annuals. Marushia, Robin; Holt, Jodie (2005)
• California’s fading wildflower legacy. Minnich, Richard A. (2004)
• Forbs working group. Pirosko, Carri; Schoenig, Steve (2004)
• Exotic plants in the Sonoran desert region, Arizona and Sonora. Devender, Thomas R. Van; Frlger, Richard S.; M., Alberto Burquez (1997)
• Fire ecology of exotic grasses in the California desert. Minnich, Richard A. (1995)
• Effects of exotic plants on three California ecosystems. Minnich, Richard A. (1994)

Other Brassica tournefortii Information

• CalPhotos - Images of plants taken mostly in California.
• Calflora - Distribution map and records of this species in California.
• CalWeedMapper - Distribution map of this species in California with ability to determine regional priorities.
• EDDMapS - Distribution of this species in North America.
• Jepson Interchange - Information on this plant's taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
• USDA PLANTS Database - Information on identification and distribution, with links to websites in individual states.

Additional photos