Persicaria capitata
Himalayan smartweed
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Family: Polygonaceae · Type: Subshrub · Not Native
Persicaria capitata (Himalayan smartweed) is a non-native California subshrub in the Polygonaceae family, recognized by distinctive head-like inflorescence and prostrate habit.
Himalayan smartweed is a naturalized perennial herb found in coastal California regions including the North Coast, Central Coast, San Francisco Bay Area, Southern California, and Peninsular Ranges in disturbed places and cultivated areas at elevations below 500 meters. Flowering from June to September, this plant produces pink-red flowers in dense, compact head-like clusters 5 to 20 millimeters wide. Growing with prostrate stems 5 to 50 centimeters long that are glabrous or glandular-hairy, it spreads readily through rhizomes. Its leaves are ovate to elliptic, typically 1.5 to 4 centimeters long, with distinctive dark blotches on the upper surface and glandular hairs on the lower surface. The compact, head-like flower clusters and pink-red blossoms make this non-native plant easily recognizable in disturbed landscapes.
Identification and appearance
Key characters: 6 sympatric species; distinctive head-like inflorescence and prostrate habit
Habitat and range
Habitat: Disturbed places; cultivated
Elevation: < 500 m
Outside California: Oregon, Louisiana, Hawaii, native to Himalayas
Bloom period
Persicaria capitata blooms Jun-Sep.
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 capitata native to California?
No. Persicaria capitata is not native to California (recorded as not native).
When does Persicaria capitata bloom?
Persicaria capitata blooms Jun-Sep.
What plant family does Persicaria capitata belong to?
Persicaria capitata is in the Polygonaceae family, genus Persicaria.
What habitat does Persicaria capitata grow in?
Persicaria capitata grows in Disturbed places; cultivated.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · 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.