Invasive plants are often beautiful but harmful species luring unsuspecting gardeners into buying a few for their home. While it may be impossible to completely eradicate some of these species, local agencies and organizations are taking steps to limit dispersion and damage on the Coastside.
Despite the potential for damage, a 2017 survey by PlantRight suggests that nearly a third of California nurseries continue to sell invasive plants on its continually updated “do not plant” list, which includes plants the organization has identified as the highest priority. When the organization finds that less than 1 percent of stores have stopped selling and growing the plants, the weeds are retired from that list.
Nearly half of known invasive plants in the state come from the nursery supply chain, PlantRight Project Manager Stephanie Falzone said. People also acquire weeds from online sellers or during travels abroad. Invasive species can be spread from clothing, animals or vehicles.
“Because invasive behavior is a regional matter (i.e. pampas grass is invasive in California, yet not in Kansas) online nursery retailers pose an especially serious threat to exacerbating the spread of invasive plants, unless the business is well informed about every invasive garden plant by state that they ship to,” Falzone wrote in an email.
The San Mateo County Department of Agriculture started monitoring online sales of these plants about six months ago. The department doesn’t find sellers in the county often, said Agricultural Commissioner Fred Crowder.
“It certainly does make things more difficult,” he said. Crowder has the authority to seize the plants and issue fines. However, most people are compliant.
“People, when we notify them, they’re like, ‘Oh my gosh, I didn’t know’ and they hand over the goods,” he said. “That’s been our experience, which is nice. People, for the most part, have an interest in protecting the environment.”
In addition, the San Mateo County Parks Department has many ongoing projects aimed at mitigating the harmful effects caused by these plants in coastal county parks.
One problem with many invasive species is that it crowds out the possibility for other plants to grow, said Hannah Ormshaw, natural resource specialist for the Parks Department.
That results in a less diverse vegetation, which provides fewer options for birds to nest and limits the types of food for wildlife to eat.
Biodiversity is one of the Midpeninsula Regional Open Space District priorities as well.
“Our (integrated pest management) program is our frontline defense to protecting the biodiversity,” Public Affairs Specialist Leigh Ann Gessner said. “... Protecting that biodiversity is a really important thing because it benefits all life, including people in our area.”
“The more biodiversity you have into an area, when you have these pest outbreaks, the ecosystem is able to respond and bounce back quite quickly, leaving a lot of the food sources that we need for our wildlife for our pollinators and also for the natural beauty that we have going on,” MROSD Supervisory Education Biologist Coty Sifuentes-Winter said.
Agencies prioritize weeds differently depending on the land they monitor.
The Parks Department focuses on jubata grass, highway ice plant, eucalyptus and Bermuda buttercup. Midpen Regional Open Space District monitors barbed goatgrass, slender false brome and French broom, among others.
In addition to the Parks Department’s ongoing work, recently acquired Tunitas Creek Beach has at least two species the department could target.
No place on the Coastside is immune from the effects of invasive species, which is why so many groups are working to control these weeds.
“Weeds are indiscriminate,” Crowder said.
In an effort to clarify PlantRight’s policies and 2017 survey, this article has been updated to include more specific information on PlantRight’s invasive plant list and how those plants are retired.