Polygonum arenastrum Jord. ex Boreau
oval-leaved knotweed (oval-leaf knotweed)
Polygonaceae (Buckwheat family)

Introduction to Vascular Plants


Once images have been obtained, photographs of this taxon will be displayed in this window.Click on the image to enter our photo gallery.
Currently no image is available for this taxon.


E-Flora BC Static Map

Distribution of Polygonum arenastrum
Click here to view the full interactive map and legend

Species Information

Annual or occasionally perennial herb from a taproot; stems prostrate, ascending or sometimes erect, several, usually 3-angled, at least when young, usually branched, the main branches 10-80 cm tall/long.
Basal leaves narrowly lanceolate to oblong-lanceolate, pale or bluish-green, the blades 5-15 mm long, unstalked, jointed at the base; stem leaves alternate, stem and branch leaves usually similar, reduced upwards; sheathing stipules silvery, 4-6 mm long, ragged.
Inflorescence of 1-5 flowers in axillary clusters; perianths 2-3 mm long, green with pink or white margins, 5-lobed more than 1/2 the distance to the base.
Achenes, with one side concave and two sides convex, brown, dull, pimply in lines,1.6-2.2 mm long.
Often mistaken for P. aviculare, a species having stem and branch leaves dissimilar.

SourceThe Illustrated Flora of British Columbia


If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.

Habitat and Range

Mesic to dry disturbed sites, roadsides and waste places in the lowland, steppe and montane zones; infrequent in S BC, rare northward to 53degreeN; introduced from Eurasia.

SourceThe Illustrated Flora of British Columbia


Synonyms and Alternate Names:
Polygonum aequale Lindm.
Polygonum aviculare var. arenastrum (Jord. ex Boreau) Rouy
Polygonum montereyense Brenckle