Sahara mustard is annual from the Mediterranean and has been spreading rapidly into coastal San Luis Obispo County. It is in Los Osos, Grover Beach, Oceano, the Nipomo Mesa and the Santa Maria River. Sahara Mustard first appeared in North America in 1927 in Coachella Valley and has spread throughout the Sonoran Desert. It grows in disturbed areas: mainly roadsides, dirt roads and construction sites. Locally it has spread from sticky seeds on pick-up truck tires, construction equipment, rodents and from wind. One of the awful qualities about this weed is that it out-competes native plants, especially annuals, simply because it grows very densely.
The 3 to 12 inch deeply lobed leaves exist as a rosette which is low, only several inches above the ground. The small, pale yellow flower stalks may reach 4 feet and produce zillions of seeds (actually up to 9,000 seeds) that are viable for more than 3 years.
Controlling Sahara mustard may be done by hand pulling. It is easier to pull than Black mustard. Sahara mustard is prolific and annoyingly often grows amongst tree and shrub plantings: pulling is the only option in this instance. It is best to pull when they are emerging. Once seed pods develop, the plant will set seed after it has been pulled, so it should be removed from the site.
When away from native plants monotypic Sahara mustard may be sprayed with Telar, Milestone, Garlon 3A or Transline (they are all broad leaf herbicides). Grazing is not a good idea because there is are toxic compounds in the seeds.
– Mark Skinner email@example.com
featured image: The pale yellow flower, with 4-7 mm petals, and siliques, growing to 3-7 cm long (David Chipping)