Naturalized in the United States and found throughout temperate North America, as well as in much of Asia and into New Zealand.
A perennial reproducing from seeds, but propagating aggressively with an extensive system of rhizomes, sometimes in chains of 2 or 3 together forming new shoots and clumps. Rhizomes are woody and very hard.
Plants thrive in marshy habitats, along canals or drainage ditches and the banks of rivers or ponds.
Mature plants grow up to 5 feet tall, with stems sharply triangular in cross section and with nearly flat sides. Several leaves grow alternate along the stem, and these are smooth, slender, and very long with a nodding habit.
Flower heads form as very open and loose clusters at the ends of the stems, and below the clusters are from 3 to 5 short secondary leaves. The flower cluster is composed of a central cluster that is not stalked, and several other spikelets coming out from it on short stalks. These spikelets are composed of 5 to 10 flower groups that are up to 1 inch long and pointed.
Characteristicts Important to Control:
Aggressively growing perennials that are found in marshy or aquatic habitats. Growth is from thick, strong rhizomes, making physical removal unlikely to be successful.