They Look Pretty, But The Yellow-Green Plants On Central And South Coast Hills Are Invasive Weeds

Apr 19, 2019

Many hillsides on the Central and South Coasts are covered with lush green and yellow flowers. Even some of the land stripped bare by the recent Thomas, Hill, and Woolsey Fires looks like it’s been revived with the help of a strong rainfall season. But, as pretty as they are, those plants are not what you think. They are black mustard, which are invasive weeds which threaten native plants.

Dr. Heather Schneider is a Rare Plant Biologist with the Santa Barbara Botanic Garden. Schneider says not only can the mustard take over land, it can literally push out other plants.

The invader is so widespread in the state that eradicating it isn’t practical. You can pull the mustard by hand, which is too labor intensive to be realistic. Chemical treatment won’t work because it would kill other plants as well.

One of the areas in the region where the invasive Black Mustard poses an especially big concern is the Santa Monica Mountains National Recreation Area. The park is home to a number of rare species of native plants.

Joey Algiers is a Restoration Ecologist with the Santa Monica Mountains National Recreation Area.  Nearly 90% of the federal land in the Recreation Area burned in the Woolsey Fire. He says they are trying to fight the invasive mustard in specific areas in the wake of the Woolsey Fire, weeding by hand to help native plants in specific spots. Algiers says in burn areas, there’s a competition of sorts between the mustard, and native plants. The mustard is better than establishing itself quickly post-fire.

The black mustard is only one of a number of non-native plant invaders on the Central and South Coasts, but it’s the most common.

But, Schneider says there is some good news. The conditions which have helped the invasive plants also created a big spring for native plants, with many rare and unusual ones blooming. And, while the “superbloom” story has faded from the headlines, there’s still some spectacular flower viewing left, and that’s expected to continue for weeks, especially at higher elevations.