Eye on Nature: A Flowering Invader


By Ellen Girardeau Kempler


Black mustard in Aliso and Woods Canyon Wilderness Park. Photo by Ellen Kempler
Black mustard in Aliso and Woods Canyon Wilderness Park. Photo by Ellen Kempler

California’s original gold arrived long before the prospectors.  Each spring, tall swaths of European black mustard cover the Golden State’s coastal wilderness in bright blooms. According to many sources, starting in the 1630s the Spanish padres  scattered mustard seeds to mark their 600-mile trail from mission to mission along California’s Camino Real.

The padres’ flowering trail had spread so far beyond its boundaries by the 1800s that it prompted Helen Hunt Jackson to write in her iconic Southern California novel, “Ramona,”  “Its gold is as distinct a value to the eye as the nugget gold is in the pocket.” On their website, the Natural Resources Conservation Service lists only four U.S. states (Texas, Alabama, North Carolina and Maryland) where this European transplant does not grow.

Reaching up to eight-feet tall, black mustard plants emerge in winter and unfurl sunny blossoms each spring during our foggiest months of May gray and June gloom. Their yellow flowers are such a cheery and familiar sight that it’s easy to forget that this annual invader does not belong in Southern California’s wilderness habitat.

What’s the harm in letting invasive weeds like Brassica nigra spread when they add color and beauty to our native landscape? According to the California Native Plant Council black mustard, like many other profusely blooming weeds, produces chemicals that prevent germination of other plants, including natives. The spread of non-natives like black mustard increases fire danger by forcing out fire-adapted species in the native coastal sage scrub and chaparral plant communities.  If allowed to grow unchecked in our wilderness, weeds like this will convert perennial native habitat, which provides a year-round home and food source for birds and other animals, to annual grassland, which does not sustain wildlife.

You can join local efforts to restore wilderness by removing invasive plants and replacing them with natives. The Laguna Canyon Foundation sponsors monthly Keep it Wild Volunteer Days at Laguna Coast and Aliso and Wood Canyons wilderness parks. For information, call OC Parks at 949-923-2235.

The former communications director of Laguna Art Museum and Laguna Canyon Foundation, Ellen Girardeau Kempler is founder and chief navigator of Laguna-based Gold Boat Journeys. She specializes in travel planning, writing, strategic marketing and social media training. Contact her at [email protected].

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