Family: Polygonaceae, Buckwheat view all from this family

Description This highly invasive weed, an upright shrubby plant with large, pointed leaves and attractive branched sprays of minute white flowers, can quickly become invasive in natural areas.
Habit: introduced perennial subshrub or herb; stems thick, smooth, hollow, jointed to resemble bamboo, often reddish; from long rhizomes.
Height: 3-12 ft (1-4 m).
Leaf: alternate, broadly oval to somewhat triangular, long pointed tip, straight wedged base, 4-6 in (10-15 cm) long, 3-4 in (7.5-10 cm) wide; on reddish stalk 0.5-1 in (1-2.5 cm) long, covered in papery sheath; turning yellow in fall.
Flower: tiny, white to greenish-white, 0.125 in (3 mm) wide; in terminal or axillary spike, 3-6 in (7.5-15 cm) long.
Fruit: black, seed-like, triangular, dangling, winged.

Flower May to September.

Habitat Open to fully shaded places, mostly wet places, but can tolerate drought: stream banks, low-lying areas, rights-of-way, roadsides, old homesteads, disturbed soil.

Range Native to eastern Asia; introduced in late 1800s as an ornamental; now naturalized throughout North America; not reported in interior or northern Canada; not reported in Florida, Alabama, North Dakota, Colorado, or from Texas west to Nevada.

Discussion Also called Japanese bamboo, Japanese arrowroot, Mexican bamboo, fleeceflower. Considered weedy and invasive in most areas; listed as noxious in many states; listed by the World Conservation Union as one of the world's 100 worst invasive species.