cultivated knotweed
U.S. Nativity: Exotic
Habit: Forbs/Herbs
Persicaria wallichii Greuter & Burdet

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Taxonomic Rank: Magnoliopsida: Polygonales: Polygonaceae
Synonym(s): Himalyan knotweed

Appearance
Persicaria wallichii is a perennial plant that can grow from 23.6-78.7 in. (60-200 cm) tall.
Foliage
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
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.
Fruit
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 from Invasive.orgView All Images at Invasive.org


Plant(s); plant.
Joseph M. DiTomaso, University of California - Davis, Bugwood.org
Additional Resolutions & Image Usage

Flower(s); flowering stem.
Joseph M. DiTomaso, University of California - Davis, Bugwood.org
Additional Resolutions & Image Usage

Foliage; foliage.
Joseph M. DiTomaso, University of California - Davis, Bugwood.org
Additional Resolutions & Image Usage

EDDMapS Distribution:
This map is incomplete and is based only on current site and county level reports made by experts and records obtained from USDA Plants Database. For more information, visit www.eddmaps.org
 


State(s) Where Reported invasive.
Based on state level agency and organization lists of invasive plants from WeedUS database.


Invasive Listing Sources:
Faith Campbell, 1998
Native Plant Society of Oregon, 2008
Pacific Northwest Exotic Pest Plant Council, 1998