Polygonum cuspidatum is a large, herbaceous perennial plant of the knotweed and buckwheat family Polygonaceae. This plant is native to China, Japan, and Korea. Hu Zhang, that medicinally mainly refers to the dried rhizomes and roots of Polygonum cuspidatum, has a variety of different names, such as Bushy Knotweed Root, Rhizoma Polygoni Cuspidati, Knotweed Rhizome, Fallopia Japonica, Giant Knotweed, Japanese Bamboo, Japanese Knotwood, Mexican Bamboo, Reynoutria Japonica, Japanese Fleece flower and so on. Best harvesting seasons are spring and autumn. After the digging, remove fibrous roots, wash clean, chop into segments or thick slices when it is fresh, dry in the sun, and used raw or fresh.