Ohio’s Noxious Weeds
Polygonum perfoliata, mile-a-minute
Family: Smartweed, Polygonaceae.
Habitat: Nurseries, roadsides, wet meadows, wood borders, other sunny, moist areas. Not yet common in Ohio, but has spread rapidly through the northeastern states.
Life cycle: Annual.
Growth Habit: Persistent vine that can extend 20 feet.
Leaves: Unique, triangle-shaped leaves with saucer-shaped sheathes near the base of stems. 1-3 inch leaves are light green, turning reddish-brown in winter, and have sharp, curved prickles on the petioles and leaf veins.
Stem: Numerous sharp, backward-curving prickles.
Flower: White, inconspicuous, borne on short spikes.
Fruit: Pea-size, berrylike, fleshy, iridescent blue fruits.
The problem is…. This troublesome annual can grow six inches per day, suffocating other vegetation in its path. Seeds spread easily through waterways or by birds and animals. The weed was introduced accidentally with nursery stock from Asia. Mile-a-minute is not yet common in Ohio, but can be found through northeastern states.
Birds and animals that eat these blue berries have spread mile-a-minute weed into new areas.
The unusual triangular leaves of mile-a-minute weed, combined with jagged prickles, make identification easy. Note the saucer-like sheathes near the base of petioles.