Rumex occidentalis
Western dock
(c) Matt Bowser, some rights reserved (CC BY) · licence
Family: Polygonaceae · Type: Perennial · Native
Rumex occidentalis (Western dock) is a native California perennial in the Polygonaceae family, recognized by . Large size and lack of tubercles distinctive.
Western dock is a California native perennial found in northern coastal, Klamath Ranges, high Cascade Range, Sierra Nevada, central Coast Ranges, Great Basin, and deltaic Great Valley regions in wet habitats at elevations below 2,500 meters. Flowering from May to August, this plant produces small greenish-red flowers in dense terminal clusters with intricate branching. Growing with stout erect stems 50 to 250 centimeters tall that are generally unbranched, it develops a substantial vertical taproot. Its large leaves are leathery, 10 to 35 centimeters long and 5 to 12 centimeters wide, with lanceolate to ovate-triangular blades featuring entire or slightly wavy margins. The fruit is a distinctive red-brown structure 3 to 4.5 millimeters long that develops from the plant's dense flower whorls.
Identification and appearance
Key characters: 18 sympatric species. Large size and lack of tubercles distinctive.
Habitat and range
Habitat: Uncommon. Wet habitats
Elevation: < 2500 m
California counties: Marin, Amador, El Dorado, Sacramento, Mono, Modoc, Fresno, Glenn, Humboldt, Mendocino, San Mateo, Siskiyou, Contra Costa, Del Norte, San Francisco, Plumas, Solano, Sonoma, Lassen, Alameda, Santa Cruz, San Luis Obispo, Shasta, Napa, Santa Barbara, Santa Clara, Yolo, Butte, San Bernardino
Outside California: western United States, Canada
Bloom period
Rumex occidentalis blooms May-Aug.
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 occidentalis native to California?
Yes. Rumex occidentalis is native to California (recorded as native).
When does Rumex occidentalis bloom?
Rumex occidentalis blooms May-Aug.
Where in California does Rumex occidentalis grow?
Rumex occidentalis occurs in Marin, Amador, El Dorado, Sacramento, Mono, Modoc, Fresno, Glenn and other counties, at elevations of < 2500 m.
What plant family does Rumex occidentalis belong to?
Rumex occidentalis is in the Polygonaceae family, genus Rumex.
What habitat does Rumex occidentalis grow in?
Rumex occidentalis grows in Uncommon. Wet habitats.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-06
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.