Ludwigia hexapetala

Ludwigia hexapetala_water primrose_Glenn Miller_cropped
Photo: Glenn Miller

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 water-primrose) 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 water-primrose mats can catch on boat and other watercraft that then spread plants to new areas.

Cal-IPC Rating: High

CDFA Rating: C*

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.

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

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.

Other Ludwigia hexapetala Information

  • CalPhotos - Images of plants taken mostly in California.
  • Calflora - See the distribution of this species on Calflora's map of California.
  • 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.
  • EDDMapS - North American distribution based on Early Detection and Distribution Mapping System.
  • Additional photos

    Ludwigia hexapetala_waterprimrose_Andrey Zharkikh_cropped
    Ludwigia hexapetala, creeping waterprimrose, close-up of flower. Photo: Andrey Zharkikh