Lythrum salicaria

Photo courtesy Bob Case

Common names: purple loosestrife

Lythrum salicaria (purple loosestrife) is a wetland herb (family Lythraceae) that invades scattered freshwater wetlands of northern and central California. Infestations are found in northern California and the San Francisco Bay Area, as well as along rivers in the southern Sierra. It is a hardy perennial that can rapidly degrade wetlands, diminishing their value for wildlife habitat.

Rating: High

Cal-IPC Resources

  • 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.
  • CalWeedMapper - Statewide maps, climate models, and reports.
  • Cal-IPC News - Our quarterly newsletter. Each issue is available as a pdf.
  • Cal-IPC Symposium Proceedings - Presentations and papers from our annual Symposium.
  • Don't Plant a Pest! - Select your region to find non-invasive alternatives to ornamental species. Also see our statewide brochure on trees.

Other Resources

Symposium Presentations

  • Benefield, C. (2000). Preventing the purple plague from taking over California's waterways. California Exotic Pest Plant Council Symposium 2000. Concord, CA.
  • Benefield, C. B. and D. Butler (2001). Purple loosestrife under siege in California. California Exotic Pest Plant Council Symposium 2001. San Diego, CA.
  • Blossey, B. (1996). The search for patterns or what determines the increased competitive ability of invasive non-indigenous plants? California Exotic Pest Plant Council Symposium '96. San Diego, CA.
  • Brown, W. Y. and A. G. Brown (1998). Campaign against invasive species: A call for action. California Exotic Pest Council '98 Symposium. Ontario, CA.
  • Butler, D. and S. Schoenig (2002). Preventing the purple plague from taking over California's wetlands. California Exotic Pest Plant Council Symposium 2002. Sacramento, CA.
  • Chornesky, E. A. and C. M. Palmer (1995). Use of biologically based methods to control pest plants:Issues related to federal research, regulation, and implementation. Proceedings California Exotic Pest Plant Council Symposium '95. Pacific Grove, CA.
  • DiTomaso, J. M. (2005). Efficacy and safety of new herbicides on the horizon. California Invasive Plant Council Symposium 2005. Chico, CA.
  • Donaldson, S. G. (1997). Flood-borne noxious weeds: Impacts on riparian areas and wetlands. California Exotic Pest Plant Council Symposium '97. Concord, CA.
  • Westbrooks, R. G. (1995). Federal regulatory efforts to minimize the introduction and impacts of exotic pest plants in the United States. CalEPPC Symposium '95. Asilomar, CA.
  • Westbrooks, R. G. (2001). Invasive species, coming to America: New strategies for biological protection through prescreening, early warning, and rapid response. California Exotic Pest Plant Council Symposium 2001. San Diego, CA.

Cal-IPC News Articles

  • Stack, L. B. (2009). Chasing weeds from Maine to California. Cal-IPC News. 16: 10,12.
  • (1995). Biological control of invasive exotic pest plant species: A report on the importance of maintaining and enhancing our nation's biological control capabilities. CalEPPCNews. 3: 6-10.
  • Pitcairn, M. (2000). All weeds that have approved biological control agents, accidental introductions and others. CalEPPC News. 8.
  • Richardson, B. (2004). The A-rated north. Cal-IPC News. 12: 4-5,14.