Persicaria longiseta is an annual forb that can reach 6-30 in. (15.2-76.2 cm) in height and can be either erect or sprawling.
Foliage
Leaves are elongate, narrow and pointed at the base and tip. Stems have swollen nodes with papery sheaths (ocrea). Ocrea have long, hair-like bristles on the margin.
Flowers
Flowering occurs from June to October, when pink flowers develop at the apex of the stems. Flowers are 0.13 in. (0.3 cm) long and occur in groups.
Fruit
Seeds are smooth, dark colored, dry, and 3 angled.
Ecological Threat
Persicaria longiseta is native to Asia and occurs in disturbed habitats such as along roadsides and in pastures. Plants also inhabit wet areas.