Knotweed Shrub Complex: Identification, Biology, and Management

Timothy S. Prather, Tim Miller-Morgan and Sandra S. Robins
PNW 610 | Published October 2009, Reviewed 2023


Being able to correctly identify the five knotweeds that grow in the Northwest can help you choose the best control strategies. Color photographs of the weeds accompany a detailed chart describing the stems, leaves, and flowers of Japanese, giant, Bohemian, and Himalayan knotweeds and low Japanese fleeceflower. Management strategies discussed include cultural, mechanical, and biological control methods as well as the use of herbicides.

About the authors

Timothy S. Prather
Associate professor in weed science
University of Idaho
Sandra S. Robins
Forest Service Botanist
United States Department of Agriculture

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