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.
Meaghan Anderson Field Agronomist in Central Iowa
Meaghan Anderson is a field agronomist in central Iowa and an extension field specialist at Iowa State University Extension and Outreach. Educational programming is available for farmers, agribusinesses, pesticide applicators, certified crop advisors, and other individuals interested in...