Japanese knotweed

Reynoutria japonica Houttuyn, Nat. Hist. 2: 640, plate 51, fig. 1. 1777

Varieties 4 (1 in the flora): introduced; Asia, intro-duced in Europe.

Fallopia japonica is planted widely as a garden ornamental; it has a proclivity to escape and spread aggressively. Once established, plants can be difficult to eradicate because of their extensive, woody rhizomes. The species has been declared noxious in Alabama, California, Oregon, Vermont, and Washington.

SELECTED REFERENCE

Beerling, D. J., J. P. Bailey, and A. P. Conolly. 1994. Fallopia japonica (Houtt.) Ronse Decraene. J. Ecol. 82: 959-979.