A group dedicated to stopping the spread of invasive plants in the nursery industry. They have a planting guide that highlights non-invasive alternatives to common invasive landscaping plants in California.
Another in-depth website dedicated to California's weeds. They have a weed ID tool that is very helpful. They also put on Weed Day at UC Davis every summer.
The book and website are a fantastic resources for identifying and managing weeds. They list biological information and non-chemical control methods, as well as detailed chemical control methods for some of the most problematic weeds in California.
Has an extensive library well written publications on various Natural Resource topics. Weed publication topics include Barbed Goatgrass, Brooms, Yellow Starthistle, Common Groundsel, and Field Bindweed.