Where it's from

Central and Eastern Europe

What Mile-a-Minute Vine/Knotweed, Asiatic tearthumb do to the habitat

This invasive plant is spreading at the rate of 150,000 acres a year in the US. It can grow at the rate of 3 feet a month.

It is known by its triangular leaves and small prickles on the vine that are irritating to the fingers.  Also called the Devil's Tear Thumb.

Dense growth reduces diversity and displaces native species.

Management

Be cautious and wear gloves as the sap can be a skin irritant. There is a biological control element -- the leafy spurge flea beetle, which is becoming more available.

DESCRIPTION

Botanical Glossary

Persicaria perfoliata is a rapidly growing herbaceous annual vine. Its stems can grow up to 7 m (23 ft.) in length and as much as 15 cm (6 in.) per day. Its dense foliage can quickly cover surrounding vegetation. A characteristic cup-shaped ocrea (or bract) surrounds the stem at the base of the petiole; those of the upper leaves are conspicuously expanded. Stems, petioles and veins on the underside of the foliage are armed with curved, retrorse barbs. The petioles are long and perfoliate. The thin, jointed, highly branched stems are green to reddish-green in color. The alternate leaves are pale green, thin and glabrous. They are 2-8 cm (0.75-3.0 in.) wide and deltoid in shape, being as long as they are wide (this leaf shape gives it one of its common names, devil's tail). The flowers are borne on racemes 1-2 cm (0.4-0.8 in.) in length that emerge from the ocrea. These inconspicuous white flowers measure 3-5 mm (0.12-0.2 in.), bear three stigmas and often remain closed. Green, berry-like fruits, 5 mm (0.2 in.) in diameter, are produced in June and become a pale, metallic blue color as they ripen. Each fruit contains a shiny, black or reddish-black, nearly round achene 2 mm (0.08 in.) in diameter. Persicaria perfoliata produces fruit continuously until the first frost, when the plant begins to die back. Dead plants in winter are reddish-brown to tan in color, often forming brittle mats. Page References Fernald 588, Gleason & Cronquist 138, Holmgren 123.