cultivated knotweed
Persicaria wallichii Greuter & Burdet


Persicaria wallichii is a perennial plant that can grow from 23.6-78.7 in. (60-200 cm) tall.
Leaves are alternate or basal, oval to lanceolate in shape, moderately hairy, and 3.9-7.9 in. (10-20 cm) long with heart shaped bases and pointed tips.
Flowers are white to pink, 0.12-0.2 in. (3-5 mm) long, fragrant, and found in clusters from 7.9-13.8 in. (20-35 cm) long. Flowers bloom from mid summer to late fall.
Seeds are dark brown in color, ovoid, 3 angled, smooth, and 0.04-0.08 in. (1-2 mm) long. They are transported mostly by water and wind.
Ecological Threat
Persicaria wallichii can be found in moist soils and in fields, pastures, and waste areas. It is native to the Himalayan region.

Selected Images


EDDMapS Distribution

EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit

State Regulated List

State Regulated List - This map identifies those states that list this species on their regulated list. For more information, visit

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Subclass: Caryophyllidae
Order: Polygonales
Family: Polygonaceae
Genus: Persicaria
Subject: Persicaria wallichii Greuter & Burdet

Synonyms and Other Names

Other Common Names:
Himalyan knotweed

Related Scientific Names:
Polygonum polystachyum Wallich ex Meisn. (Synonym)


Plants - Forbs/Herbs


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