Undaria pinnatifida

Photo: Carol Thornber, Univ. Rhode Island

Common names: wakame; Japanese kelp; Asian seaweed

Undaria pinnatifida (wakame) is an annual algae (family Alariaceae) first recorded in several estuaries in California in 2000. Wakame is native to Japan, where it is consumed for its food value and as a nutritional supplement. In California, wakame usually cannot compete with native perennial brown algae, but it may colonize estuaries rapidly if native algae are not present. Hence, wakame occurs in high densities only in recently disturbed areas. Although it does not appear to have serious impacts in California, it has been a very serious invader in New Zealand.

Cal-IPC Rating: Limited?

CDFA Rating: None?


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

No Weed RIC Management Notes are available for this species. Check for information on other species in the genus on the Weed RIC site.

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 Undaria pinnatifida Information

  • 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.
  • Additional photos

    Undaria pinnatifida_sporophyll and base of mature frond_JoeDiTomaso
    Undaria pinnatifida (wakame) sporophyll and base of mature frond. Photo: Joe DiTomaso
    Undaria pinnatifida_young frond (left) and sporophyll frond (right)_JoeDiTomaso
    Undaria pinnatifida (wakame) young frond (left) and sporophyll frond (right). Photo: Joe DiTomaso