Rumex obtusifolius
Bitter dock
(c) Bruce Calvert, some rights reserved (CC BY), uploaded by Bruce Calvert · licence
Family: Polygonaceae · Type: Herb · Not Native
Rumex obtusifolius (Bitter dock) is a non-native California herb in the Polygonaceae family, recognized by . Large, broadly ovate leaves with cordate base distinctive.
Bitter dock is a naturalized perennial herb found in northern California coastal regions, the Great Valley, central coastal areas, San Francisco Bay Area, and southern coastal regions in moist places at elevations below 2,000 meters. Flowering from May to September, this plant produces small greenish flowers in dense, interrupted whorls along branching stems. Growing 60 to 120 centimeters tall with generally branched stems, it develops a vertical taproot and spreads readily in disturbed areas. Its large leaves are widely ovate to oblong, 20 to 40 centimeters long with a heart-shaped base and entire margins, creating a distinctive broad-leafed appearance. The fruit is small, measuring 2 to 2.7 millimeters long and turning brown to red-brown when mature.
Identification and appearance
Key characters: 19 sympatric species. Large, broadly ovate leaves with cordate base distinctive.
Habitat and range
Habitat: Moist places
Elevation: < 2000 m
California counties: Orange, Ventura, San Bernardino, Sonoma, Del Norte, Riverside, Los Angeles, Humboldt, San Diego, Kern, Imperial, Mendocino, Contra Costa, El Dorado, Butte, Calaveras, Placer, Santa Clara, Santa Cruz, Shasta, Solano, Trinity, Marin, Nevada, San Francisco, Santa Barbara, Siskiyou, San Joaquin, Colusa, Sierra, Alpine, Alameda, Tuolumne, San Mateo, Monterey
Outside California: throughout North America, native to Europe, western Asia
Bloom period
Rumex obtusifolius blooms May-Sep.
How to tell it apart
vs Anemopsis: Rumex has dense flower clusters; Anemopsis has a single white cone-like flower head.; vs Amaranthus: Rumex has papery three-winged fruits; Amaranthus has small round seeds with papery covers.; vs Plantago: Rumex has branching flower clusters; Plantago has flowers in dense cylindrical spikes.; vs Eriogonum: Rumex has large broad leaves; Eriogonum typically has small basal leaf rosettes or mats.; vs Limonium: Rumex has green to reddish flower clusters; Limonium has papery purple or pink flowers.
Frequently asked questions
Is Rumex obtusifolius native to California?
No. Rumex obtusifolius is not native to California (recorded as not native).
When does Rumex obtusifolius bloom?
Rumex obtusifolius blooms May-Sep.
Where in California does Rumex obtusifolius grow?
Rumex obtusifolius occurs in Orange, Ventura, San Bernardino, Sonoma, Del Norte, Riverside, Los Angeles, Humboldt and other counties, at elevations of < 2000 m.
What plant family does Rumex obtusifolius belong to?
Rumex obtusifolius is in the Polygonaceae family, genus Rumex.
What habitat does Rumex obtusifolius grow in?
Rumex obtusifolius grows in Moist places.
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.