Mustard seeds – Image Credit
Legend has it that as the Spanish Franciscan fathers wended their way up and down California long ago in the Mission Period, they spread European mustard seed. The story was that the bright yellow flowers would act as a sort of pathway from one mission to the next, each about a day’s travel apart by horseback, or three days on foot. Clever idea, if it’s really true, but over time the “pathway” took off and went just about everywhere. Mustard covers fields and hillsides all over California. Vineyards, of which there are untold acres in California, are often thickly filled with mustard during times of dormancy for the grapevines. Before the vines get going in later spring, vintners mow the mustard down, but the roots of mustard, and the ground up mulch left on the ground have chemicals in them that discourage nematodes, a root problem for grapes.
California Vineyard with mustard grass – Image Credit
Mustard comes in a variety of species which hybridize, so there are a lot of different kinds of the plant out there. One of the most common along the coast is Brassica nigra, or black mustard, which grows quite tall and is the stuff you probably see the most of as you (locals) drive up the Gaviota Coast. The “black” part of the name has nothing to do with the flowers, which are that day-glo yellow that bursts upon the scene in spring, i.e. February. This is especially true in years of good rain, and though we are in a who-knows-how-many-years-long drought, there has been enough rain to bring it out in force already. This ability to take advantage of a little local rain allows mustard to thrive through all but the most dessicated years. Its seeds have been known to bide their time for as long as 20 years, waiting for adequate moisture to germinate. In other words, mustard is here, and we’ll never get rid of it.
Why would we want to? It’s so colorful and pretty and bright and brings delight to travellers! Unfortunately, it also grows so densely and quickly that it outcompetes the native vegetation. Sucking up water and creating shade, the real Californians don’t get much of a chance to thrive. So what, you might say – lots of those natives only have tiny little flowers or grow close to the ground – not much of a show. The problem, as with all rampant invasives, is the diminishment of biodiversity. California native plants have evolved in place for millennia and fit their ecosystem perfectly. They work with the soil, the weather, the bugs, the bees, the native foragers and predators. It’s all in balance, and a staggering achievement of biology and time. When an invasive shows up, perhaps far from the bugs and diseases that kept it in check where it was a native itself, there’s not much to keep it from growing out of control and overpowering the unique garden of natives. It’s a quiet upheaval, and if you don’t know the facts, it just looks like a fabulous display of nature. But the loss of a community thousands or millions of years in the making is kind of tragic. Brassica tournefortii or Sahara mustard, another invasive, has found a home in drier climates within the state and beyond. It now poses a fire hazard in desert areas which formerly did not have the kind of fuel its prolific growth provides. When man moves plants around the planet for the purpose of decoration or cultivation or even just by accident, the consequences are unpredictable, but usually not widely beneficial, especially to the local vegetation.