Knotweed is a common name for plants in several genera in the family Polygonaceae. Knotweed may refer to:
- Fallopia
- Persicaria
- Polygonum
- Reynoutria
- Reynoutria japonica or Japanese knotweed, a highly invasive species in Europe and North America
Knotweed is a common name for plants in several genera in the family Polygonaceae. Knotweed may refer to: