“MOST WANTED DEAD!” The Invasive Sahara Mustard
The invasive plant Brassica tournefortii Gouan is commonly referred to as Sahara mustard, wild turnip, African mustard, or Asian mustard and grows from four to forty inches tall. It threatens to invade and change the Mojave Desert to an extent that will be irreversible if its seed production is not stopped now. The dense stands of Sahara mustard that have been seen growing along our roadways and washes during and after the heavy rains in recent years has produced a bounty of seeds that are ready to produce even more plants and spread ever wider in the next growing season. Botanists know that well-developed plants can produce between 750 and 9,000 seeds.
The Sahara mustard has the potential to dominate the available soil moisture at the expense of the native Mojave annuals that begin their growth cycle a little later in the season. This alien also has the capacity to increase fuel loads and fire hazard in desert scrub.
Because seed banks in the soils of the Morongo Basin are relatively new and follow our vehicular byways and the washes that are nearby, it’s possible that quick action can result in controlling and preventing the spread of this invasive plant by destroying the plants that do come up before they produce flowers and seeds. According to the University of Nevada:
- “The best control method for any invasive plant is prevention. People must be made aware and given the tools for early identification in order to prevent ingress and establishment of alien species in new areas. If Sahara mustard is found, eliminate it immediately. Do not allow it to go to flower and produce seed.” - University of Nevada Fact Sheet FS-05-02
Much research remains to be done as to the natural history and methods for best controlling Sahara mustard. So far, it is clear that it is best to remove the plants before they begin to send up their flowering parts. If pulled after that they must be bagged and destroyed---they are capable of flowering and going to seed even after being pulled. They also are able to re-root themselves, so even when quite small simply pulling them up and leaving them on the ground is not sufficient; they must be dismembered or removed.
What we can do:
The Morongo Basin Conservation Association is working to eradicate Sahara mustard in our communities before it’s too late, but it’s a massive challenge. We need everyone to learn how to identify mustard and how to destroy it.
Because a single plant can produce thousands of seeds, and the seeds are viable for years, Basin residents can expect the need for removing new sprouts to be ongoing. We encourage residents to “adopt-a-block”, whether their own yard, a nearby roadway or field, or any area they care about, and make repeat visits to clear it of mustard. Getting the seedlings when they’re small is easy, quick, and a whole lot easier than wrestling with the plants and their seeds when they’re larger. Staying on top of the mustard season after season is our best defense. Over time, the number of plants will diminish.
MBCA has developed a full-color, illustrated educational brochure to inform residents about the Sahara mustard, how to identify it, and how to eradicate it. To receive a brochure for you or your group contact MBCA. (Funding for printing the brochure was made possible through a grant from the Desert Legacy Fund at The Community Foundation serving Riverside and San Bernardino Counties.)
You can also print directly from this Website the MBCA “Pull Me!” flyer (PDF): quick mustard facts, how-to-pull tips, and identifying photos. Print these, hand them out to neighbors, and spread the word, instead of the seeds! (Thanks to MBCA member Donna Thomas for creating the flyer.)
MBCA has also been working with Joshua Tree National Park to remove mustard from Park lands. Volunteers are critical to keeping this invasive from threatening natives and adding dangerously to the fuel load in the Park. If you’re interested in being on our list of volunteers, please contact our Hold the Mustard Chairperson.
MBCA is developing the Hold the Mustard! program in coordination with Joshua Tree National Park and the Mojave Desert Resource Conservation District. As part of the Mojave Weed Management Area a range survey is currently in progress, to be followed by creation of a regional plan. Presentations on the Sahara mustard invasion and plan control strategies from a 2005 multi-state meeting in Barstow, CA (sponsored by Caltrans and the Federal Highway Administration) are accessible at the California Invasive Plant Council.