Ronse Decraene, Reynoutria japonica Houtt. Noxious clumping perennials with large leaves, hollow stems, and long creeping rhizomes .
Plants grow vigorously and create dense colonies that exclude other vegetation.
Established colonies are extremely difficult to eradicate. All three were introduced as garden ornamentals, but have widely escaped cultivation and become invasive in moist, disturbed places. To 3 m tall . Colonies are especially problematic in the Eastern U.S. Young shoots, stems, and rhizomes are edible. Plants are used medicinally in China and Japan.