mile-a-minute vine, Asiatic tearthumb Persicariaperfoliata (L.) H. Gross
Appearance
Persicaria perfoliata is an herbaceous, annual vine that invades disturbed areas in Oregon and portions of the northeastern United States. The delicate stems are reddish, highly branched and covered with small, curved spines. Circular, leafy structures (ocreae) surround the stem at the base of the petioles.
Foliage
The alternate leaves are triangular, light green, 1-3 in. (2.5-7.6 cm) wide and barbed on the undersurface.
Flowers
Small, white, inconspicuous flowers arise from the ocreae.
Fruit
Fruit are present in mid-July through the first frost, are metallic blue and segmented with each segment containing a single black or reddish black seed.
Ecological Threat
Persicaria perfoliata invades open disturbed areas such as fields, forest edges, roadsides, ditches and stream banks. Its rapid growth allows it to cover existing vegetation and restrict light availability, potentially killing plants below. Dense mats of Persicaria perfoliata can also restrict establishment of new vegetation. It is native to Eastern Asia and the Philippines and was introduced several times into the United States from the late 1800s to the 1930s.