Source: California Invasive Plant Council
URL of this page: http://www.cal-ipc.org/ip/management/plant_profiles/Alternanthera_philoxeroides.php
Alternanthera philoxeroides (alligatorweed)

Alternanthera philoxeroides
Photo courtesy Joseph DiTomaso
Alternanthera philoxeroides (alligatorweed) is a noxious herbaceous aquatic perennial (family Amaranthaceae), that forms dense floating mats. This weed grows in the San Joaquin Valley (Tulare and Kings counties) and in Los Angeles County. It invades lakes, streams, canals, ponds and irrigation ditches. It was previously used in the aquarium trade.
Cal-IPC Inventory rating: High
Cal-IPC Resources on Alternanthera philoxeroides
- California Invasive Plant Inventory Assessment Form (pdf) - 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 News - Articles from our quarterly newsletter. Each issue is available as a pdf. List of articles on Alternanthera philoxeroides.
- Cal-IPC Symposium Proceedings - Presentations and papers from our annual Symposium. List of articles on Alternanthera philoxeroides.
Cal-IPC News Articles
- Pitcairn, M. (2000). All weeds that have approved biological control agents, accidental introductions and others. CalEPPC News. 8.
Cal-IPC Symposium Proceedings
- 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.
- Leavitt, J. R. and C. Pirosko (2002). A brief overview of the California Dept. of Food and Agriculture's A-rated noxious weed education and eradication program. California Exotic Pest Plant Council Symposium 2002. Sacramento, CA.
- O'Connell, R. A. (1997). Hydrilla: A case study: The state of California's noxious weed eradication programs. California Exotic Pest Plant Council Symposium '97. Concord, CA.
- O'Connell, R. A. (1999). The state of California's noxious weed eradication programs. California Exotic Pest Plant Council. Sacramento, CA.
Other Resources on Alternanthera philoxeroides
- USDA PLANTS database - Federal database with information on identification and distribution, and links to websites in individual states.
- Jepson Online Interchange for California Flora - Information on taxonomy, biology, and distribution from the UC Berkeley Jepson Herbarium.
- CalFlora - Distribution information by county based on submitted observations and herbarium specimens.
- The Nature Conservancy Element Stewardship Abstract - Information compiled by TNC land managers. Photos included for some species.
- Encycloweedia - Plants rated as noxious weeds by the California Department of Food and Agriculture.
- CalPhotos - Images of plants taken mostly in California.
- Natural Resource Projects Inventory - State database with information on resource management projects throughout California. Query by the species of interest.
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