Watchlist and Invasive Plant Alerts

Carduus nutans (musk thistle) has a limited range but the potential to spread.

Photo courtesy Joseph DiTomaso

Download Cal-IPC's Watchlist: Excel spreadsheet or pdf. Last updated December 2011.

Cal-IPC's Watchlist compiles information on plants not yet on our statewide Invasive Plant Inventory that land managers have reported escaping in wildlands. Some of these plants were previously evaluated for our statewide Invasive Plant Inventory but were not added to the Inventory due to lack of information or limited distribution within California. More information will allow us to re-consider these species. For each species, the Watchlist includes where and in what habitat types it has been reported, and where else in the world it is invasive. This watchlist will be updated as we receive new information.

We encourage Cal-IPC members to report potentially significant invasions of plants new to an area. Not only does this provide an initial time frame for the invasion, but also alerts land managers in other regions of the state to the potential threat. Rapid action on a new invader can potentially save millions of dollars with preventative control or even eradication. Please send reports of new species to Elizabeth Brusati, edbrusati@cal-ipc.org.

The "Red Alerts" differ from the Alert designation within the Invasive Plant Inventory, which refers to plants with High or Moderate ratings that have the potential to increase their ranges in California.

"Red Alerts" from the Cal-IPC Symposium

At our annual Symposium, Dr. Joe DiTomaso of the Department of Plant Sciences at UC Davis presents information on new invasive plants and range expansions. The presentations below (pdfs) contain photographs and details on these species, also listed in our watchlist. Species already included on Cal-IPC's Inventory also have Plant Profiles.