Polygonum perfoliatum

Common Name: Mile-a-minute (a.k.a. Minute weed, Mile-a-minute vine, Giant climbing tear-thumb)
Scientific Name: Polygonum perfoliatum
Family: Polygonaceae
Growth Form: Herbaceous vine
Native Range: India to Eastern Asia and Japan
Invasive Range: Well established in Pennsylvania, Maryland and West Virginia, but spreading north and west. 
Introduction: The first occurrence of mile-a-minute weed resulting in the plants naturalization occurred in York County, Pennsylvania in the 1930s.  A nursery owner allowed the plant to grow, and it escaped into the surrounding area.  Mile-a-minute weed reproduces by seeds, which are dispersed by birds and ants. 
Description: ·Leaves: Alternate, simple, triangular, or sometimes heart-shaped.  3-8 cm (1.5-3 in.) long.  Untoothed with abrasive margins.  Light green, but can be red when young. Petioles are longer than leaf, have 1-2 mm spines, with leaf-like sheath where it meets the stem called ocrea.

·Stem:  Green, branched, can grow up to 7 m in length (21 ft.).  Can become woody with age.  Have 1-2 mm spines.  Red or brown at base. 

·Flowers: Light green or yellow, rarely pink.  3-5 mm (0.25 in) long.  Appear in 1-2 cm long spike that protrudes from ocrea.  Present from July to August.

·Fruit: Shiny black achene inside of metallic blue perianth resembling a berry.  Present from September to November.
Threats: Mile-a-minute weed grows quickly, forming dense mats over existing vegetation, and inhibiting their ability to photosynthesize.  It is especially bad for Christmas tree farms and nurseries because it can smother tree seedlings. 
Fun Facts: In traditional Chinese medicine, mile-a-minute weed is used as an anti-inflammatory and diuretic.
Vine with leaves, inflorescence and fruit