Knotweed Complex

Growth Habit: Herbaceous perennial, shrub-like, clusters of unbranched stalks from base, 4 to 12 feet tall. Leaves: Varies slightly by species, large, 5 to 12+ inches, alternate, entire, heart-shaped to lanceolate, leathery, some species have hair on midvein. Stems: Hollow, swollen at nodes, jointed giving a zigzag appearance in some species. Flowers: Panicles of many tiny white to pink sometimes pale green flowers, some species have small panicles while others have large panicles, but all are delicate, borne in leaf axils or at stem and branch tips. Roots: Extensive horizontally, and vertically, frequent shoots arising from root stocks. Reproduction: seeds: 3 sided achenes, usually brown, sometimes black, seeds are not the primary means of spread; vegetative: extensive reproduction from creeping rhizomes creating dense stands, some species capable of reproducing new plants from each node on stem

Complex of species including: giant, Japanese, and Bohemian knotweed (Fallopia spp.) and Himalayan knotweed (Persicaria wallichii)

Native to Europe and Asia.