Washingtonia robusta

Washingtonia robusta_Mexican fan palm_JM DiTomaso
Photo courtesy Joseph DiTomaso

Synonyms: W. filamentosa (often mistaken for native W. filifera)

Common names: Mexican fan palm; Washington palm; skyduster; thread palm

Washingtonia robusta (Mexican fan palm) is a single-trunked palm tree (family Arecaceae) found in the San Francisco Bay area, southern Sacramento Valley and on California’s south coast. Mexican fan palm is a common landscape ornamental that has become invasive in riparian areas, orchards and landscaped areas. This palm is known to create monospecific stands in riparian areas, and dead fronds of the tree can create a fire hazard. The species can be controlled with relative ease by removing the seedlings.

Cal-IPC Rating: Moderate

Cal-IPC Assessment

Plant Assessment Form - Information gathered by Cal-IPC on the impacts, rate of spread, and distribution of invasive plants in California. Does not include management information.

Cal-IPC Newsletter Articles

Cal-IPC Symposium Presentations

  • Kelly, M., B. Peterson, et al. (2007). Drilling and injecting two invasive palm species. California Invasive Plant Council Symposium 2007. San Diego, CA, California Invasive Plant Council.
  • Burkhart, B. and M. Kelly (2007). How to develop user-friendly riparian corridor invasive exotic species/habitat restoration master plans: Experiences on the San Diego and Otay Rivers. California Invasive Plant Council Symposium 2007. San Diego, CA, California Invasive Plant Council.
  • Kelly, M. (2001). Drilling as a technique for controlling eucalyptus, palms & other exotic trees. California Exotic Pest Plant Council Symposium 2001. San Diego, CA.
  • Tu, M. and J. M. Randall (2002). 2002 Red alert! New introductions and recent expansions in California. California Exotic Pest Plant Council Symposium 2002. Sacramento, CA.
  • Tu, M. and J. M. Randall (2003). 2003 Cal-IPC red alert! New invasions, recent expansions, and a few others to be on the look-out For. California Invasive Plant Council Symposium 2003. Kings Beach, CA.

Other Washingtonia robusta Information

  • CalFlora - Distribution information based on submitted observations and herbarium specimens.
  • CalWeedMapper - Distribution information with ability to determine regional priorities.
  • Jepson Online Interchange for California Flora - Information on taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
  • USDA PLANTS Database - Federal database with information on identification and distribution, and links to websites in individual states.