Polygonum virginianum
From Nearctica
Identification: Flowers small and white, sparsely spaced along an extremely long, apical, flowering stalk. Leaves ovate, tapering to a sharp apex and into a short petiole. Leaves large, alternate, hairy. Junction of stem and leaf swollen with a tubular, papery sheath. Plant 1 to 4 feet in height.
Distribution: Minnesota to Nova Scotia, southward to Florida and Texas.
Habitat: Virginia Knotweed is found in forest and thickets.
Flowering period: July to October.
Similar Species: The elongate flowering stalk and the large, hairy leaves should easily identify this species.