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Invasive Species: Mile-A-Minute Weed
Other names: Asiatic tearthumb
*Detected in Michigan*
- Fast-growing annual vine with leaves shaped like equilateral triangles.
- Narrow, delicate, green or red stems.
- Recurved barbs on stems and undersides of leaf blades.
- Alternate, light green leaves, 1”-3” wide.
- Individual, round leaves (ocreae) encircle the stem below the flower/fruit spike.
- Small white flowers in early summer.
- Spikes of pea-sized blue fruit appear in July.
Mile-a-minute weed leaves are light green and triangular. Photo courtesy of Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Small, curved barbs line the stem and leaf blade. Photo courtesy of Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Small, blue berries grow in spikes above circular leaves that wrap the stem. Photo courtesy of Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Mile-a-minute weed can overtake and smother trees and shrubs. Photo courtesy of Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
REPORT THIS SPECIES
If you see mile-a-minute weed, take one or more photos, make note of the location, date and time of the observation, and report to:
The Midwest Invasive Species Information Network (MISIN) online reporting tool.
Or - download the MISIN smartphone app and report from your phone - MISIN.MSU.edu/Tools/Apps/#Home
ABOUT THIS SPECIES
Habitat: This herbaceous, annual, trailing vine colonizes open and disturbed areas with a preference for very wet soil. Typical infestation areas include stream banks, open space, roadsides, forest edges, and fence lines. Mile-a-minute weed thrives with abundant sunlight and uses its recurved barbs to attach to and climb over other plants.
Native Range: India to Eastern Asia, China and islands from Japan to the Philippines
U.S. Distribution: Reported in Connecticut, Delaware, Massachusetts, Maryland, Michigan, Mississippi, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, Virginia, West Virginia and Washington.
Michigan Distribution: Identified in Calhoun County.
Michigan Status: Mile-a-minute weed is on Michigan’s watch list.
Local Concern: Mile-a-minute weed can grow up to 25’ in six to eight weeks. Dense, prickly thickets overtake native vegetation. Christmas tree farms, orchards, reforestation and restoration areas are at risk because of the vine’s propensity to smother tree and plant seedlings. Seeds may survive in the soil for up to six years.
Means of Introduction or Spread: Each fruit contains a single seed, and vines can produce up to 3,500 seeds per year. Fruits are eaten by birds, deer and small mammals which can spread seeds miles away from the original plant.
Control: As an annual, mile-a-minute weed can be controlled by regular tilling or mowing to prevent flowering or seeding. Young and mature plants can be removed manually before fruits ripen. Double bag all plant material and allow to decompose in sunlight for several days before removing waste to a landfill or incinerator. Infested areas should be monitored regularly for regrowth.