Wildflowers of the United States

Virginia Knotweed, Jumpseed - Persicaria virginiana

Genus Common Name: Smartweed

Native Status: Native

Dicot Annual Perennial Herb

Persicaria virginiana - Virginia Knotweed, Jumpseed. The Polygonum genus has recently been split into multiple genera, with about 30 species being reclassified in the genus Persicaria. I am following the lead of others in changing this from Polygonum virginianum to Persicaria virginiana. The genus common name for Persicaria is now "Smartweed"; Polygonum had been "Knotweed". The text imbedded in the photos will continue to reflect the old classification.

Persicaria virginiana is a late summer plant mostly of most woodlands, found in most of the eastern half of the United States.

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Distribution of Persicaria virginiana in the United States and Canada:

Map courtesy of The Biota of North America Program.
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Site: Reflection Riding, Hamilton County, TN Date: 2010-September-11	Photographer: Gerald C. Williamson Nikon D60 Tamron SP 90MM f/2.8 AF Macro
This photo shows what most folks will notice first about this plant – the thin elongated raceme of tiny white knots, that may be up to 2 feet long, frequently as long or longer than the rest of the plant. There may be multiple racemes on a single plant.

Site: Reflection Riding, Hamilton County, TN Date: 2010-September-11	Photographer: Gerald C Williamson Nikon D60 Tamron SP 90MM f/2.8 AF Macro
Each blossom is greenish white to pale pink on a short pedicel. It has 4 tiny tepals each around 1/10th of an inch long.
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Site: Reflection Riding, Hamilton County, TN Date: 2010-September-11	Photographer: Gerald C Williamson Nikon D60 Tamron SP 90MM f/2.8 AF Macro
The seed forms with the style remaning on it. Pressure on the style of a mature seed will cause it to jump off of the plant for dispersal, giving Virginia Knotweed another common name of Jumpseed.
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Site: Reflection Riding, Hamilton County, TN Date: 2010-September-11	Photographer: Gerald C Williamson Nikon D60 Tamron SP 90MM f/2.8 AF Macro
The alternate leaves of Polygonum virginianum are on a short petioles. They are ovate with a somewhat elongated, sharp tip.
Click on the photo for a larger image

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Persicaria virginiana initially published on USWildflowers.com 2010-09-13; Updated 2015-06-24

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Code Update 20230302