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 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

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 - 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.
  • Additional photos

    Ludwigia hexapetala_waterprimrose_Andrey Zharkikh_cropped
    Ludwigia hexapetala (creeping waterprimrose) close-up of flower. Photo: Andrey Zharkikh
    Ludwigia hexapetala_infestation_copyright2014_NealKramer
    Ludwigia hexapetala (creeping waterprimrose) infestation. Photo: &#169 2014 Neal Kramer
    Ludwigia hexapetala_leaf, stem, bracts, and flower_copyright2014_NealKramer
    Ludwigia hexapetala (creeping waterprimrose) leaf, stem, bracts, and flower. Photo: &#169 2014 Neal Kramer