Fallopia sachalinensis

Photo courtesy Joseph DiTomaso

Synonyms: Polygonum sachalinense; Reynoutia sachalinensis

Common names: giant knotweed; sakhalin knotweed; sacaline

Fallopia sachalinensis (Sakhalin knotweed) is a perennial forb/herb (family Polygonaceae). Plants grow vigorously and create dense colonies that exclude other vegetation. Established colonies are extremely difficult to eradicate. It inhabits disturbed moist sites, roadsides, riparian and wetland areas. Plants typically grow in open, sunny areas on moist soils in cool temperate climates. Very little of this species occurs in California. It is a much bigger problem in the Northwestern US.

Rating: Moderate

Cal-IPC Resources

  • 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.
  • Cal-IPC News - Our quarterly newsletter. Each issue is available as a pdf.
  • Cal-IPC Symposium Proceedings - Presentations and papers from our annual Symposium.
  • Don't Plant a Pest! - Select your region to find non-invasive alternatives to ornamental species. Also see our statewide brochure on trees.

    Other Resources

    Symposium Presentations

    • Crockett, R. P. and M. L. Krebsbach (2004). The new “JK Injection Tool” for control of knotweeds and other hollow-stem plants growing in sensitive wetland sites. California Invasive Plant Council Symposium 2004. Ventura, CA.
    • Tu, M. and J. M. Randall (2003). 2003 Cal-IPC red alert! New invasions, recent expansions, and a few others to be on the look-out For. California Invasive Plant Council Symposium 2003. Kings Beach, CA.

    Cal-IPC News Articles

    • Brusati, E. (2005). Japanese knotweed (Polygonum cuspidatum) and other knotweeds. Cal-IPC News. 13: 10.