Persicaria pensylvanica
Pinkweed
(c) Sandy Wolkenberg, some rights reserved (CC BY), uploaded by Sandy Wolkenberg · licence
Family: Polygonaceae · Type: Herb · Not Native
Persicaria pensylvanica (Pinkweed) is a non-native California herb in the Polygonaceae family, recognized by essentially bristle-less ocrea and dense uninterrupted spikes.
Pinkweed is a naturalized annual herb found in eastern Sacramento Valley and other disturbed habitats, typically in moist places like riverbanks and drying ponds at elevations around 30 meters. Flowering from May to December, this plant produces white to pink flowers in dense, erect clusters with yellow, pink, or red anthers. Growing 10 to 200 centimeters tall with ascending to erect stems that are glabrous or lightly hairy, it spreads readily in open, damp environments. Its lance-shaped leaves measure 4 to 17 centimeters long with tapered bases and acuminate tips, often showing dark blotches on the upper surface. The fruit is a shiny, lens-shaped or three-angled structure 2 to 3.4 millimeters long, turning from brown to black when mature.
Identification and appearance
Key characters: 6 sympatric species; essentially bristle-less ocrea and dense uninterrupted spikes
Habitat and range
Habitat: Moist disturbed places, drying ponds, riverbanks, fields
Elevation: +- 30 m.
California counties: Sonoma, Mendocino, Merced, San Diego, Butte, Sacramento, San Bernardino, Monterey
Outside California: native to eastern United States, introduced otherwise in North America, Europe
Bloom period
Persicaria pensylvanica blooms May-Dec.
How to tell it apart
vs Polygonum: Persicaria has opaque stem sheaths; Polygonum has translucent sheaths that split into two lobes.; vs Rumex: Persicaria has spike-like pink/white flower clusters; Rumex has branched greenish flower clusters.; vs Trifolium: Persicaria has spike/head flower clusters and papery stem sheaths; Trifolium has clover heads and no sheaths.; vs Salix: Persicaria is an herb with flower spikes; Salix is a woody shrub with catkins.; vs Phytolacca: Persicaria has small pink/white flowers in spikes; Phytolacca has white-green flowers and dark purple berries.
Frequently asked questions
Is Persicaria pensylvanica native to California?
No. Persicaria pensylvanica is not native to California (recorded as not native).
When does Persicaria pensylvanica bloom?
Persicaria pensylvanica blooms May-Dec.
Where in California does Persicaria pensylvanica grow?
Persicaria pensylvanica occurs in Sonoma, Mendocino, Merced, San Diego, Butte, Sacramento, San Bernardino, Monterey, at elevations of +- 30 m..
What plant family does Persicaria pensylvanica belong to?
Persicaria pensylvanica is in the Polygonaceae family, genus Persicaria.
What habitat does Persicaria pensylvanica grow in?
Persicaria pensylvanica grows in Moist disturbed places, drying ponds, riverbanks, fields.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.