Bohemian Knotweed
Bohemian knotweed (Polygonum x bohemica) is the hybrid created from a cross between Japanese knotweed (Polygonum cuspidatum) and giant knotweed (Polygonum sachalinense). Originated from Asia, knotweeds were imported to the United States for ornamental use and stream bank stabilization. Bohemian knotweed is characterized by having hollow stems up to ten feet tall, broad oval shaped leaves, small white flowers, and underground stems used for vegetative reproduction called rhizomes. Small pieces of stems or roots are known to produce new plants, making the spread of Bohemian knotweed very easy with the movement of soil. Once established, Bohemian knotweed spreads quick forming dense stands preventing native vegetation re-growth.
In Kansas, Bohemian knotweed was first reported growing on a small residential lot in southwest Topeka. Since its conformation, KDA has been working with the homeowner to eradicate the population. Roundup is very effective in controlling the above ground biomass, but repeated applications are necessary to control the extensive root and rhizome structures underground.