Synonyms: Jussiaea grandiflora (M. Michelli) Greuter & Burdet; Jussiaea repens L var. grandiflora M. Michelli; Jussiaea uruguayensis Camb.; Ludwigia uruguanyensis (Camb.) Hara var. major (Hassler) Munz
Common names: creeping waterprimrose; Uruguay waterprimrose
Ludwigia hexapetala (Uruguay waterprimrose) is an aquatic plant (family Onagraceae) that forms dense mats in waterways, reaching above and below the water surface. This dense growth impedes water movement, blocks the growth of native plants, and reduces available habitat for waterbirds and fish. Although this species has been naturalized in California for at least 25 years, it has grown exponentially in the past several years, leading to increased concern over its impacts on waterways. Pieces of Uruguay waterprimrose mats can catch on boat and other watercraft that then spread plants to new areas.Cal-IPC Rating: High?
CDFA Rating: C*?
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.
Weed Management Notes
- Management Notes - Information on management techniques and effectiveness from the University of California Cooperative Extension’s Weed Research & Information Center.
Cal-IPC Newsletter Articles
- Aquatic weed management in the Delta. Johnson, Doug. Vol 31, Issue 1
- Wildland Weed News. Cal-IPC. Vol 24, Issue 1
- Lessons from Ludwigia control in Sonoma County. Meisler, Julian. Vol 17, Issue 3
Cal-IPC Symposium Presentations
Presentations are linked where available. Where a presentation is not available, find more information by reading the abstract in the Cal-IPC Symposia Archive.
- Biological control of aquatic weeds in California: Status update and a look to the future. Pratt, Paul (2023)
- Ecosystem engineering impacts of water primrose in the Delta. Morrison, Bailey (2023)
- Invasive species holobiomes as bioindicators? Environmental DNA metabarcoding from community-collected CALeDNA samples makes holobiomes available for common invasive plants. Meyer, Rachel (2020)
- Warm temperatures increase biomass of seedling: implication for management of Ludwigia hexapetala and Ludwigia peploides subsp. montevidensis. Gillard, Morgane; Grewell, Brenda; Futrell, Caryn; Deleu, Carole; Thiébaut, Gabrielle (2018)
Other Ludwigia hexapetala Information
- CalPhotos - Images of plants taken mostly in California.
- Calflora - Distribution map and records of this species in California.
- CalWeedMapper - Distribution map of this species in California with ability to determine regional priorities.
- EDDMapS - Distribution of this species in North America.
- Jepson Interchange - Information on this plant's taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
- USDA PLANTS Database - Information on identification and distribution, with links to websites in individual states.