There are several places to obtain information about particular species.

1. First, find out the scientific name of the species you are interested in- this will make it easier to search, as there may be many common names for a species. For example, Erechtites glomerata is called cutleaf fireweed, cutleaf burnweed, New Zealand fireweed and Australian burnweed. Also, some common names refer to more than one species; iceplant refers to both Carpobrotus edulis and Carpobrotus chilensis, but also is used for non-invasive groundcovers such as Delosperma cooperii. A good place for a layperson to start is the USDA Plant Database . In the search window (upper left), select common name and put in some or all of the common name you are looking for. You may need to be persistent: entering starthistle or star thistle returns nothing, whereas star-thistle returns the 6 different Centaurea species that have this as part of their name. If the common name you are looking for doesn't show up go step 2, otherwise skip to step 3.
2. The Jepson Interchange is a comprehensive set of references but it is rather technical, and can be overwhelming for the layperson. Also be advised that the Jepson Manual is undergoing revision and many taxonomic classifications are changing.
3. Once, you have found the USDA Plant Database page(s) for the weed of interest, check the images to verify the identification. Try the Calphotos link near the bottom of the page for even more images.
4. The list of  related pages at the very bottom of the USDA Plant Database page frequently has links that contain management information for the species. In the next items I'll discuss a few of those, as well as others to try.
5. The Weed Research and Information Center (WRIC) provides specific identification and management advice about many species, as well as more general advice about developing a long-term integrated vegetation management plan, an important component of any successful strategy. However, not all of Mendocino County's invasive plants are treated individually on this site.
6. The California Invasive Plant Council's (Cal-IPC) Invasive Plant Profiles  has an extensive list of species that are covered individually in their database. For example, you will find a page for gorse here, while this species is not covered specifically in the WRIC site (although many of the WRIC suggestions for woody species are also relevant for gorse). Selecting a species, by common or scientific name, will lead you to a list of further references. I suggest you start with ...
7. Species Accounts from Invasive Plants of California Wildlands, if available. Published in 2000, this contains fairly recent management information.
8. General internet search (Google , Yahoo , ...). New information on weed management is coming out all the time. Searching for the scientific name and a keyword such as "weed" or "management" will generally return only useful links.
9. If you haven't found what you need, please contact the WMA staff or the Agriculture Department through our Contact Us page.