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Japanese Knotweed, Mexican Bamboo, Japanese Bamboo
Family: Polygonaceae;
Genus: Polygonum;
Species: cuspidatum;
Synonyms:
Reynoutria japonica
Growth Form: Forb
General:
Perrenial herb, but grows to 3 - 9 ft. tall, spreads primarily vegetatively.
Flowers:
White-pink, densely crowded on erect to drooping stalks.
Fruits and Seeds:
Small winged fruits. Seeds triangular, shiny and very small, about 1/10 inch long.
Leaves:
Simple, alternate, 6 in. long by 3 - 4 in. wide, broadly oval to somewhat triangular and pointed at the tip.
Stems or Branches:
Branching, reddish-brown, smooth, and swollen at leaf joints.
Threatens:
Riparian corridors, fens, springs. Also grows along roadsides. Full sun to full shade.
Look-Alikes:
Giant Knotweed (P. sachalinense), exotic invader, leaves deeply heart-shaped with rounded basal lobes.
Distribution:
Native to E Asia, known from NE, SE, Midwest and NW.
Other Links:
http://www.invasive.org/eastern/biocontrol/12Knotweed.html
http://www.invasivespeciesinfo.gov/plants/knotweed.shtml
http://www.nature.org/wherewework/northamerica/states/connecticut/science/art323.html
http://www.umext.maine.edu/onlinepubs/htmpubs/2511.htm
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Illinois Distribution
USDA Plants DB 5.7.08
Flowers
Leslie J. Mehrhoff, University of Connecticut
Leaves
Jack Ranney, University of Tennessee
Roadside incursion
Leslie J. Mehrhoff, University of Connecticut
North American Distribution
USDA Plants DB 5.7.08
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