- Polygonum perfoliatum is a fast growing herbaceous annual vine. Stems grow up to 6 in. (15 cm) a day; 23 ft. (7 m) in length total.
- A cup-shaped ocrea surrounds the stem at petiole base; in upper leaves the ocrea is much larger. Stems, petioles and veins under leaves bear curved, retrorse barbs; petioles long and perfoliate; thin, jointed, highly branched stems green to reddish-green. Leaves alternate; pale green; thin; glabrous; 0.75-3.0 in. (2-8 cm) wide; deltoid in shape; and as long as they are wide.
- Small white flowers 0.12-0.2 in. (3-5 mm); on racemes 0.4-0.8 in. (1-2 cm) long; emerge from the ocrea; bear three stigmas; and often remain closed.
- Green, berry-like fruits, 0.2 in. (5 mm) diameter; appear in June; ripen to a pale, metallic blue; contain a black or reddish-black, rounded achene 0.08 in. (2 mm) diameter; and is produced continuously until the first frost.
- Ecological Threat
- It cover and outcompete native vegetation. The weight of the vine can damage trees and other plants. Its transportation in nursery stock is a problem, because it may accidently be planted with other plants. It’s found in open disturbed areas, old agricultural fields, roadsides, stream edges and wet meadows. It has been seen spreading into early successional forest and climbing trees up to 13 ft. (4 m) high.
- Stone, Katharine R. 2010. Polygonum perfoliatum, Fire Effects Information System, U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory
- Global Invasive Species Database. 2011. Invasive Species Specialist Group (ISSG) of the IUCN Species Survival Commission
- Invasive Plant Atlas of New England (IPANE)
- Connecticut Invasive Plant Working Group
- Flora of China, www.eFloras.org
- USDA NRCS PLANTS
- USDA ARS GRIN