Pinkweed

Pinkweed (Persicaria pensylvanica) is in the knotweed family family (Polygonaceae). Across the U.S., iNaturalist users have logged 876 research-grade flowering observations of it in our sample, peaking in September.

Nationally it blooms mainly from August to September, but timing varies a lot by state and elevation — see the table below.

When to photograph Pinkweed: observations by month (U.S.)

About Pinkweed

Persicaria pensylvanica (syn. Polygonum pensylvanicum) is a species of flowering plant in the buckwheat family, Polygonaceae. It is native to parts of North America, where it is widespread in Canada and the United States. It has also been noted as an introduced species in parts of Europe and South America. Common names include Pennsylvania smartweed and pinkweed.From Wikipedia via iNaturalist — article, CC BY-SA.

Pinkweed by state

Main season = months with at least 30% of the state's peak-month count.

Related wildflowers (knotweed family)

California BuckwheatEriogonum fasciculatum

Low SmartweedPersicaria longiseta

Desert TrumpetEriogonum inflatum

Sulfur BuckwheatEriogonum umbellatum

American jumpseedPersicaria virginiana

Naked BuckwheatEriogonum nudum

Japanese knotweedReynoutria japonica

American bistortBistorta bistortoides

Photography tips

• Photograph flowers on calm, overcast mornings to avoid wind blur and harsh shadows.
• Get low: a shallow depth of field (f/2.8–f/5.6) isolates a bloom against soft color.
• Stay on trails — trampling meadows kills plants and ruins next year's display.
• Try a kaleidoscope abstract of a single bloom with our online kaleidoscope tool.

FAQ