Noxious Weeds

The Watershed Center’s weed management team (a combination of volunteer and paid youth conservation crew labor) has targeted  populations of spotted knapweed (Centaurea stroebe var micranthos) and scotch broom (Cytisus scoparius) within the South Fork Trinity River basin. These species are a top priority for treatment. If we can control their populations before they become overwhelming, we have a chance to eradicate them.

Spotted Knapweed is an extremely aggressive plant that is difficult to control. It can bolt and produce flowers in its first year, live up to nine years, and produce up to 40,000 seeds annually. Seeds remain viable in the soil for at least seven years. The roots produce a toxin that kills other plants severely reducing forage for wildlife and livestock. Knapweed does not prevent erosion like native grasses do and limits water absorption into the soil.

Scotch Broom is a highly invasive woody weed. It grows rapidly, crowding out native plants and preventing re-growth, retarding or preventing the growth of many understory species, and preventing the re-growth of forests, leading to a dramatic loss of diversity. It forms dense thickets, shelters feral animals, reduces food for native wildlife, blocks paths and chokes creeks. Scotch broom also changes soil chemistry, making it unsuitable for local native plants.

The Watershed Center is working with the National Forest Foundation, the US Forest Service, the Trinity County Resource Conservation District,  the California Invasive Plants Council and the Department of Conservation on multiple noxious weed initiatives. Participate in a weed pulling party; sign up as part of our volunteer program, the South Fork Basin Stewards, by calling our office at 530.628.4206.

Volunteers chipping freshly pulled scotch broom.

Knapweed on the banks of the South Fork Trinity River.