Origin
Native to Eurasia and North America.

Appearance
Polygonum aviculare is a mostly prostrate summer annual, with hairless stems up to 36″ (91 cm) long.

Foliage
The alternate oblong leaves are about 1″ by 0.33″ and smooth with entire margins. The leaves often have a blue-green appearance.

Flowers
Flowers have five petals (sepals) that can range from white to pink to purple, but with white margins. Small clusters of flowers arise from the leaf axils.

Fruit
The fruit is a three-sided achene (one seed) that is reddish-brown to brown.

Ecological Threat
P. aviculare forms think mats which outcompete many other plants. It inhabits disturbed areas such as roadsides, compacted soil along paths, and waste areas with barren ground. P. aviculare is more tolerant of road salt and pollution than most species.

https://www.fs.fed.us/database/feis/plants/forb/polavi/all.html
https://www.illinoiswildflowers.info/weeds/plants/pros_knotweed.htm

Selected Images

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Maps

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Invasive Listing Sources

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• Invasive Plant Species of West Virginia
• National Park Service, Mid-Atlantic Exotic Plant Management Team Invasive Plant List
• West Virginia Native Plant Society, Flora West Virginia Project, and West Virginia Curatorial Database System, September 3, 1999

References

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Common Name Reference: USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.

Scientific Name Reference: USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.