Knotweed, Knotgrass, Bistort

This is another genus that is under study by taxonomists. Therefore, the number of species to include ranges from a low of about 65 up to a high of over 300.

A genus of many alternate leaved species of herbs or climbing plants with simple leaves, numerous small flowers (consisting only of a calyx and 5 sepals) in spikes, heads or racemes. Some species may become invasive.

The name is Greek, poly, meaning "many" and gonu, meaning "knees".





Polygonum affine  
P. amplexicaule Mountain Fleece
P. aubertii Silver Fleece Vine
P. bistorta Snakeweed
P. capitatum Pinkhead Knotweed
P.cuspidaturn Japanese Knotweed
Mexican Bamboo
P. cuspidaturn var. compacturn  
P. euspidaturn Japanese Fleeceflower
P. hydropiper Smartweed     
P. milettii  
P. orientale Prince's Feather
P. pensylvanicum Pennsylvania Smartweed
P. persicaria Lady's Thumb
P. reynoutria Reynoutria Fleeceflower
P. sachalinense Giant Knotweed
P. scandens Hedge Bindweed
P. vaeelniifolium Rose Carpet Knotweed

Species Hgt (in) Flower Color
P. affine 6-9 Rose-red
P. bistorta 18-30 Pink
P. nilettii 18-24 Crimson

* Guides and Keys are from the book "Herbaceous Perennial Plants A Treatise on their Identification, Culture and Garden Attributes" by Dr Allan M. Armitage of the University of Georgia. Varsity Press, Athens, Georgia. 1989 ISBN 0-942375-00. More on Dr Armitage and his other books.


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