It has a pretty yellow flower and covers the hills of some of our Walnut Creek open spaces.
But it is also a major non-native, invasive weed. When an infestation takes hold, it can "reduce wildlife habitat and foraging opportunities, displace native plants, and decrease native plant and animal diversity," according to a study cited by the UC Davis Weed and Research Information Center.
Some Walnut Creek residents are taking action to clean up an infestation of this plant in the Shell Ridge Open Space. The star thistle originated somewhere in Asian Minor and was probably introduced to the United States sometime after 1849 as a seed contaminant in Chilean-grown alfalfa seed. And, boy, did it spread.
A small group of residents, based in the Lakewood neighborhood, is starting to go up to the Shell Ridge Open Space to weed out the highly invasive Yellow Star Thistle. These residents are inviting others to come along and join their efforts to rid the open space of this "particularly brutal invader," says Phil Johnson, a locally-raised landscape contractor who is leading the group.
Johnson acknowledges that many plants growing in the wild around here are non-native, including the grasses, but Yellow Star Thistle is especially nasty, because it "doesn't play well with others."
"We have a chance to prevent it from becoming established in our open space," says Johnson, who can help volunteers identify the species and effectively remove them.
The group will probably meet up on Wednesday afternoons between 4 and 4:30 p.m. for about an hour and a half. They plan to do these "weed-ups," (as I'll call them) through the end of April. The group is putting together a Facebook page, which will have more details about volunteering (times, locations, and what, if anything you should wear or bring).
Stay tuned, eager warriors in the battle against the damn Yellow Star Thistle. When I get that Facebook link, I'll post it here.