Asia
Mile-a-minute weed is a climbing, branching annual vine that grows up to 20 ft (6 m) long from a shallow root system. Stems, leaf petioles, and the undersides of leaf veins are covered in recurved spines. Leaves are alternate, triangular, and up to 3 in (7½ cm) long. Saucer-shaped ocrea surround the stem at each leaf node. Flowers are green and inconspicuous. Fruits are berry-like, blue at maturity, and each produces one hard, shiny black seed.
Mile-a-minute weed competes with other plants for limited resources, displacing more desirable species. It forms large mats that smother, shade out, and can even break shrubs and small trees in native and commercial forests. It is a nuisance in landscaping, nurseries, orchards, and transportation rights-of-way. The recurved spines covering the vines hinder movement of wildlife and recreationalists.
Hough-Goldstein, J. and E.C. Lake. 2022. Mile-A-Minute Weed (Persicaria perfoliata): History and Ecology in North America. In: R.L. Winston, Ed. Biological Control of Weeds in North America. North American Invasive Species Management Association, Milwaukee, WI. NAISMA-BCW-2022-11-MILE A MINUTE WEED-P. https://bugwoodcloud.org/resource/files/26409.pdf