Bohemian knotweed is a vigorous and fertile hybrid that is the result of a cross between Japanese and giant knotweed.
Physical Description
There is a high degree of morphological variability in Bohemian knotweed. Physical characteristics of Bohemian knotweed range from being indistinguishable from Japanese knotweed to being indistinguishable from giant knotweed, with most individuals exhibiting intermittent characteristics between the 2 species.
- Broadly ovate to narrowly ovate leaves, 7 to 14 inches long, with a flat to heart-shaped base
- 6 to 11 feet tall
- Green segmented stems, with or without red to brown spotting, that are variable in width
- Stout leaf hairs up to 1/2 mm long
- The cross section of the middle leaf vein is square to slightly rounded in shape
- Papery sheaths between stem sections
- Hollow stems
- Cream colored, sweet-smelling, linear flower bunches at each leaf. That often appears to have a more upright appearance than Japanese or giant knotweed
Control Efforts
Bohemian knotweed infestations take several years of treatment to control, and the most effective method is repeated herbicide application. Contacting a natural resource professional as early as possible is integral to knotweed control. If you see giant knotweed, contact the Oregon Invasives Hotline as well as the Lincoln Soil and Water Conservation District (LSWCD) by phone at (541) 265-2653 or email Lincoln SWCD.