prostrate knotweed

(Polygonum aviculare)

prostrate knotweed

Prostrate knotweed is a very widespread and very common annual herb. Its origin is uncertain but it is thought to be native to Europe, Asia, and North America. Its spread has been greatly assisted by humans. It is now naturalized on every continent except Antarctica. It is found in bottomland forests, marshes, swamps, bottomland prairies, pastures, agricultural fields, farmyards, ditches, roadsides, railroads, lawns, and sidewalk cracks, and on banks of rivers, streams, lakes, and ponds.


There are six subspecies of prostrate knotweed in North America, five of which occur in Minnesota. They vary greatly in appearance. However, in areas where two subspecies occur, populations intergrade in a complex way. According to Flora of North America, this makes identification to the subspecies level impractical.

The stems are flexible, semi-erect to sprawling, and 1 to 6 long. The nodes are translucent, becoming jagged. The sap is highly acidic but clear, not milky. The leaves are green or grayish-green and variable in shape. Leaf blades may be narrowly ellipse-shaped, egg-shaped, or spatula-shaped. Flowers appear in small clusters at the leaf axils. Flowers are produced from August to October. The flowers may be green or reddish-brown, and may have white, pink, or reddish margins. The outer 3 petal-like sepals are not longer than the petals, however this is not visible without a hand lens.


Distribution Map



2, 3, 4, 5, 7, 22, 28, 29, 30.

  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Magnoliopsida (flowering plants)  
  Superorder Caryophyllanae  


Caryophyllales (pinks, cactuses, and allies)  


Polygonaceae (knotweed)  
  Subfamily Polygonoideae  
  Tribe Polygoneae  
  Subtribe Polygoninae  


Polygonum (knotweed)  

Subordinate Taxa


box knotweed (Polygonum aviculare ssp. buxiforme)

common knotweed (Polygonum aviculare ssp. aviculare)

narrow-leaf knotweed (Polygonum aviculare ssp. neglectum)

narrow-leaf knotweed (Polygonum aviculare ssp. rurivagum)

northern knotweed (Polygonum aviculare ssp. boreale)

oval-leaf knotweed (Polygonum aviculare ssp. depressum)




Polygonum aviculare var. vegetum

Polygonum heterophyllum

Polygonum monspeliense


Common Names


prostrate knotweed

yard knotweed











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  Polygonum aviculare
Susanne Wiik
  Polygonum aviculare  

Tungress, Knotgrass

  Polygonum aviculare
Matt Lavin
  Polygonum aviculare  

Introduced annual (and perennial) with generally prostrate stems, whitish tepals tinged with rose, common in highly disturbed settings including along sides of roads, trails, sidewalks, lawns, curbs, and similar town settings.

  Polygonum aviculare
Cristina Corral

Cristina Corral




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  Polygonum aviculare

Uploaded on Oct 8, 2008

Polygonum aviculare
(Corvinus beszámoló)

  EL CIENNUDOS: Polygonum aviculare (
Published on Sep 14, 2012

Published on Sep 14, 2012

El Ciennudos (Polygonum aviculare) es una planta herbácea anual de la familia Polygonaceae y origen en Europa.

Su desarrollo es rastrero pudiendo llegar a 1 m de longitud. Puede tomar carácter erguido en determinadas condiciones. Los tallos parten de un punto central, donde se unen a la raíz, y se extienden radialmente ramificándose. Tiene nudos y entrenudos. De los nudos salen las hojas y flores y, de algunos, salen nuevas ramas. Son de color verde oscuro grisáceo, con líneas longitudinales.

Las hojas son simples, de peciolo muy corto, de forma elíptica, con el borde liso y color verde oscuro a glauco.

Las flores son pequeñas, solitarias o en grupos pequeños, apareciendo en la axila de las hojas. Tienen la corola con cinco pétalos de color blanco a rosado.

El fruto es un aquenio.

En la naturaleza se da en zonas ruderales y campos de cultivo y barbechos. Es una buena cobertora de suelos para evitar la erosión en las etapas iniciales de restauración.

Más información sobre El Ciennudos (Polygonum aviculare) en:




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