Polygonaceae (VI)

The knotweed family (Polygonaceae) is a family of dicot plants. They are usually herbs, but also climbing plants, shrubs and trees. The name is derived from their articulated stems with clearly recognizable, numerous nodes.

The family is found worldwide, with an emphasis on temperate regions. It includes 1,200 species spread over 48 genera. The largest genera are Eriogonum (240 species) and Rumex (200 species).

Part of it is planted as an ornamental plant or as a food source with buckwheat (Fagopyrum esculentum) and rhubarb (Rheum rhabarbarum) as the best-known products. But Polygonaceae contain the most harmful weeds, including the Japanese knotweed (Fallopia japonica). This invasive species is considered harmful because the plant has a negative effect on biodiversity due to its strong vigor. The plant is highly invasive and, once established, very difficult to control. Due to its vigor and relative insensitivity to pesticides, the Japanese knotweed is difficult to kill in places where it is once well established.