Coefficient of Conservatism:
Coefficient of Wetness:
JAPANESE KNOTWEED, MEXICAN BAMBOO
A. A. Reznicek
Polygonum cuspidatum of Michigan Flora.
A native of Japan, planted as an ornamental and found as an escape at gravel pits, filled ground, roadsides, dumps, and gullies. First collected in 1919 in Wayne Co.
Both this species and F. sachalinensis grow from sturdy rhizomes and are difficult to eradicate once established. They form dense thickets as tall as 2 m or more. Whenever there is a report of “bamboo” in Michigan, it is likely to be based on one of these stout species, which have hollow internodes (true bamboos are grasses and very rarely known to escape in Michigan; see Phyllostachys). Some specimens from Alcona, Ingham, and Newaygo Cos. are apparently the hybrid F. ×bohemica (Chrtek & Chrtková) J. P. Bailey; see Zika & Jacobson (2003) for more information.