Myriophyllum aquaticum

Myriophyllum_aquaticum_By André Karwath
Photo: André Karwath, via Wikimedia Commons

Synonyms: Enhydria aquatica, Myriophyllum brasiliense, M. proserpinacoides

Common names: parrotfeather; Brazilian watermilfoil; parrotfeather watermilfoil; thread-of-life;

Myriophyllum aquaticum (parrotfeather) is a stout aquatic perennial (family Haloragaceae) that forms dense mats of intertwined brownish stems (rhizomes) in water. Myriophyllum aquaticum can be found in freshwater lakes, ponds, and canals with slow-moving waters in northern and central California. This invasive plant may compete with native aquatic plants, eliminating them or reducing their numbers in infested sites. It forms dense mats that can entirely cover the surface of the water in shallow lakes and other waterways. The species does not produce viable seed and its distribution is limited to vegetative dispersal mechanisms.

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 Myriophyllum aquaticum 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

    Myriophyllum aquaticum_leaves and stem with adventitious roots_ZoyaAkulova
    Myriophyllum aquaticum (parrotfeather) leaves and stem with adventitious roots. Photo: Zoya Akulova
    Myriophyllum aquaticum_growth habit_ZoyaAkulova
    Myriophyllum aquaticum (parrotfeather) growth habit. Photo: Zoya Akulova
    Myriophyllum aquaticum_infestation_ZoyaAkulova
    Myriophyllum aquaticum (parrotfeather) infestation. Photo: Zoya Akulova