JAPANESE KNOTWEED - Polygonum cuspidatum Sieb. & Zucc.

Polygonaceae - (Buckwheat family)

Perennial from long creeping rhizomes.  Stems are stout, reddish-brown, 4 to 9 feet tall, woody but die back at end of growing season.  The nodes are slightly swollen and surrounded by thin paper sheaths.  Leaves are short-petioled, broadly ovate, 2 to 6 inches long and about two-thirds as wide, narrowed to a point.  The flowers are greenish white to cream, borne in large plume-like clusters at ends of stems and in leaf axils.  The fruit is 3-sided, black and shiny.

Introduced from Asia as an ornamental, now escaped to become a weed of roadsides, waste areas, ditch banks, and pastures.

(Courtesy of Weeds of the West)

Control Strategies coming soon.

NOTE: All Pesticide application recommendations are based on label directions and experience with these products in Fremont County Wyoming. However, labels change from time to time. Ultimately it is the responsibility of the applicator to insure the pesticide application is made within the directions on the current product label. If you are unsure of, or have questions concerning treatment method or a chemical usage please consult your local Weed & Pest office, or a licensed professional.