Chinese knotweed

noun3

1. •
   A flowering plant of species Persicaria chinensis, from the family Polygonaceae, widespread across China, Japan, the Indian Subcontinent, Indonesia, Malaysia, and Vietnam, used as an ingredient in herbal remedies.
2. •
   A flowering plant of species Reynoutria multiflora, in the family Polygonaceae, native to central and southern China, whose roots are an important ingredient in traditional Chinese medicine.
3. •
   A large, perennial, rhizomatous herb, of species Koenigia weyrichii, native to East Asia.