Fields of Yellow: Mustard Bloom

The vibrant super-blooms that have blanketed California’s valleys and hillsides the past few years have brought out people eager to witness the spectacle — and document it for their social media channels — in hordes.
Photo by Deborah J. Albre.


From January until the end of March, one of the most beloved sights is the mustard bloom: fields of perky yellow flowers as far as the eye can see. There are conflicting stories about the origin of these nonnative plants. Some reports claim Russian settlers unknowingly brought the seeds in wheat sacks during the 1800s; others say a Jesuit priest, Father Jose Altimira, introduced the plant here.

Either way, this resilient herb has become controversial. Since it’s highly effective at aerating soil and mining minerals deep in the earth, some grape growers plow mustard into the ground after the March bloom to condition the soil. The downside: mustard is linked to accelerating fires and doesn’t hold soils well due to its shallow roots, adding to the threat of erosion in burned areas. Moreover, its dead stalks produce a chemical that inhibits other plants’ ability to grow around it. Invasive plants cost California at least $82 million each year. Here in Marin, the Marin Municipal Water District annually spends approximately $500,000 on fire-fuel reduction and invasive plant control. Help preserve the biodiversity and safety of our area by not planting mustard and other weedy species, pretty as they may be. For more information, see the invasive plant list and suggested alternatives on

Categories: Environment, Marin Matters