Long-bristled Smartweed

(Polygonum caespitosum)

Long-bristled Smartweed (Polygonum caespitosum L.)

Alien: Native of Japan.

Identification: Flowers pink (sometimes white), small, arranged in tightly packed, narrow spikes. Stem swollen at the junction of a leaf and the stem, and with a papery sheath around the stem. Upper margin of the sheath with a fringe of elongate, hairlike spines, spines as long as visible sheath. Leaves elongate, narrow, tapering toward both the base and the apex. Plant either erect or sprawling on the ground. Plant 6 to 24 inches in height.

Distribution: Throughout eastern and central North America.

Habitat: Long-bristled Smartweed is a weedy species fond in disturbed habitats such as lawns, along roadsides, and in wet areas.

Flowering period: June to October.

Similar Species: Long-Bristled Smartweed is very similar to Lady's Thumb. However Long-bristled Smartweed lacks dark blotches along the midline of the leaf. The hairlike spines of Long Bristled Smartweed are very long, as long as the visible portion of the sheath. Lady's Thumb has spines, but they are much shorter.