The rains are here and weeds are thriving, including the dreaded Sahara mustard, Brassica tournefortii.When the wastewater construction disturbed the soil all over Los Osos it engendered a huge crop of this highly invasive plant. It is beginning to flower now, so NOW is the time to pull it, before it goes to seed.

Numerous Old World mustards have invaded North America. Of these Sahara mustard is the newest and by far the worst. It really is a monster! It is a robust, fast-growing, drought-tolerant winter annual that prefers sandy soils. The basal rosette of divided hairy leaves can span three feet in wet years. The nearly leafless flowering stems branch profusely and grow to a height of about two feet, creating the appearance of a shrub from a distance.

These highly invasive plants especially thrive in disturbed soil.  And they self-pollinate, so one large plant can produce 16,000 seeds.  Here’s the important part: Sahara Mustard easily and quickly outcompetes native plants that nourish our wildlife.  Without native flora, we lose our native fauna.

The plants have rough, hairy leaves that get smaller as they move up the stem.  They can be as short as 4 inches or as tall as 40 inches.  The flower is tiny, pale yellow, composed of four symmetrical petals.

We are asking all Los Osos residents to take at least one hour in the next several weeks to track down and remove these nasty plants wherever you can find them in our community.  Pull them up by the root and place in a green waste bin or the garbage.  Don’t assume the county can handle this.  Our county deputy agricultural commissioner says, “If Sahara mustard gets a foothold the way veldt grass has, widespread control will simply be impractical.”

When Sahara mustard is pulled out early, before it goes to seed, it does not seem to return. Three years ago, a huge batch of the week was from the corner of Don and Mitchell. It has not returned. We can get ahead of it.

You can find Sahara mustard in almost any vacant lot in the sewer-construction zone.  Local resident Bonnie Thompson, whose articles have appeared in the Tribune about this weed said, “Places where I’ve seen burgeoning growth recently include the north side of Santa Ysabel between 10th and 11th Streets, and the corner of 18th and the El Moro bike path; and across the street, on the edge of the open land.  And all along Pismo Street, starting at the Middle School and continuing on to the bay.”  If you look for it, you will find it.  Don’t worry if you accidentally pull another species of mustard; they are all non-native introduced plants.

Here’s how you can help:

1.) Spend at least one hour in your yard and neighborhood pulling up these dangerously invasive weeds.  

2.) Tell as many people as you can.

3.) Plant natives

3.) If you use Facebook, LIKE us at and check the page out occasionally for updates, information, and pretty photos too.

And we’d love to hear back from you regarding your efforts to rid Los Osos/Baywood of this noxious interloper. Tell us about your experience on our Facebook page or post a note on Nextdoor, the neighborhood on-line network. 

Celebrate Los Osos is a 501(c)( 3) non-profit organization, dedicated to making a difference, one project at a time, with highly visible projects, engaging volunteers who want to get their hands dirty “doing good work” for the benefit of our unique community. See our (antique) website for a list of our past projects: