Tuesday May 27, 2025
Los Angeles Times —
The Sepulveda Basin Wildlife Reserve suffers from many of the ills that might be expected of a natural area located in the middle of the nation’s second-largest city, including litter and even biohazards such as discarded needles from nearby drug use.
But on Saturday morning a few hundred volunteers had another culprit in their sights: Rhamphospermum nigrum, a nonnative plant better known as black mustard that has flourished in the 225-acre reserve and the wider Sepulveda Basin Recreation Area.
The plant, with its four-petaled yellow flowers in bloom, fills the basin’s meadows and paints a bucolic picture that belies what it really is — an invasive weed that crowds out native plants such as sage and poppy that are crucial to the health of the basin, its natural wildlife and the Los Angeles River that runs through it.
“It does look harmless, but it becomes a mono crop, and this is the main enemy to biodiversity,” said Dan Mott, environmental educator with Friends of the Los Angeles River, which held the event with the California Native Plant Society and San Fernando Valley Audubon Society. “The native species can’t be here, and all the birds and the insects that are supposed to be in this area, they don’t want the mustard.”