Common names: Pink knotweed, Pinkhead smartweed. Scientific name: Persicaria capitata. Synonyms: Polygonum capitatum. Family: Polygonaceae. Genus: Persicaria.

Plant type: Annual or Perennial. Flowering time: Jun-Sep. The leaves are 1-6 cm long, 0.7-3 cm wide, ovate to elliptic. Flower color: Pink. Persicaria capitata is a native of Asia.