Pennsylvania smartweed

Encyclopedia Article

Pennsylvania smartweed                        Persicaria pensylvanicum L.

Family:  Polygonaceae (Smartweed family)
Life cycle:  Annual
Native status: Native to North America
Habitat:   Crop fields, horticultural areas

General description:  Erect or ascending growth with stems reaching 3 ft in length.  Stems are smooth, branched, often with reddish tint, and swollen nodes.  Leaves are alternate, elliptic, with ochrea at base of the petiole.  Leaves occasionally have purple spot in center.  Pink to white flowers are small and arranged in dense, elongated clusters up to 3 in long.

Key ID traits:  Alternate, elliptic leaves with ochrea; ascending growth habit.

Similar species:  Ladysthumb has a very similar growth habit and vegetative characteristics to Pennsylvania smartweed, and is found in similar habitats.  The ochrea of ladysthumb has hairs on the margin, whereas PA smartweed lacks the hairs.

Miscellaneous: Previously classified as Polygonum pensylvanicum.

Pennsylvania smartweed with cotyledons.

Narrow, lanceolate leaves of Pennsylvania smartweed.

The ochrea is a membranous structure at base of leaf petiole found on members of the smartweed family.


Pink flowers on inflorescence.


Patch of Pennsylvania smartweed.