If you mention the terms "weed" and "California" in the same sentence, some people will make an assumption about the subject at hand. NPS areas in the San Francisco area are looking for some volunteer "weed watchers," and the purpose of this project may be different than you expect.

National Park Service sites in the San Francisco Bay area are looking for some help in the battle against invasive species, and they're offering two training sessions in mid-May for volunteer "weed watchers" willing to search out and report locations where these pests are trying to gain a foothold.

If the old definition of a "weed"—a plant growing in the wrong place—still holds true, there are plenty of weeds in parks around San Francisco Bay. According to information from the NPS, approximately 32 percent of the plant species in the National Parks of the San Francisco Bay Area are non-native.

Among them are highly invasive species, such as French broom or pampas grass, which spread rapidly and alter the landscape and scenery in and around our parks. Not only do they change the visitor experience, they may increase fire risk, destroy habitat for rare or endangered plants and animals, and become very expensive to control as they continue to spread.

Those are all valid reasons to combat the spread of these pests, and this is one example of ways citizens can get involved to help their parks.

Scientists have found if they can locate highly invasive plant species before they become widely established, it is far more cost effective to control them than to wait until the plants have spread over many acres. The parks have identified at least 200 species of highly invasive plants that are not yet wide spread but could spread quickly if they become established. Among them are periwinkle, capeweed, Portugese broom, purple starthistle, and many others.

There are certainly not enough staff members to keep a watchful eye for these plants on every acre in parks, but volunteers in the Weed Watcher Program are helping prevent the spread of new invasive plant species. The program has been used at Golden Gate National Recreation Area, Muir Woods National Monument, Pinnacles National Monument, and Point Reyes National Seashore.

What's involved if you sign up as a weed watcher?

Volunteers learn to identify species that are highly invasive and search for them along roads and trails, where many alien plants first become established. By locating and mapping new invasive plant species, the parks can respond by removing these alien species before they become established. For example, last year 19 volunteers put in more than 1050 hours and helped survey over 350 miles of routes. Due to these efforts by our volunteers, much of the plant infestations have already been removed by park staff.

Point Reyes National Seashore is hosting two training sessions for anyone interested in participating as a Weed Watcher. The workshops will be held on Thursday, May 13, and Sunday, May 16, from 10 a.m. to 1:30 p.m. in the Red Barn Classroom at 1 Bear Valley Rd, Point Reyes Station, California. If you'd like to attend the training, RSVP to Natalie Howe at 415-464-5201 or by email.

More information about the program and about additional training sessions in the Bay Area is available at this link.