Cardamine occidentalis
Big western bittercress
(c) Gabriel Campbell-Martinez, some rights reserved (CC BY) · licence
Family: Brassicaceae · Type: Herb · Native
Cardamine occidentalis (Big western bittercress) is a native California herb in the Brassicaceae family, recognized by large fleshy rhizome and 5-7 leaflets diagnostic.
Big western bittercress is a California native perennial found in northwestern California in wet soils, lake margins, and creek habitats at elevations of 150 to 1,500 meters. Flowering from March to May, this plant produces delicate white flowers 4 to 6 millimeters long with distinctive white petals. Growing with erect or ascending stems 10 to 50 centimeters tall, it develops fleshy rhizomes and can be simple or branched. Its leaves are pinnately compound with 5 to 7 leaflets, the terminal leaflet round to widely ovate, 0.5 to 2 centimeters long, with entire or wavy margins. The plant produces elongated fruits 1.5 to 3.5 centimeters long, carried on spreading-ascending pedicels.
Identification and appearance
Key characters: 8 sympatric species; large fleshy rhizome and 5-7 leaflets diagnostic
Habitat and range
Habitat: Wet soils, lake margins, creeks
Elevation: 150-1500 m
Outside California: to Alaska
Bloom period
Cardamine occidentalis blooms Mar-May.
How to tell it apart
vs Raphanus: Cardamine has narrow pencil-like pods with many seeds; Raphanus has thick beaked pods that break into segments.; vs Nasturtium: Cardamine grows on moist land in shade; Nasturtium grows in or at the edge of water in sun.; vs Viola: Cardamine has four petals and thin seed pods; Viola has five petals and a capsule that splits into three parts.; vs Vancouveria: Cardamine has four-petaled flowers and seed pods; Vancouveria has six-petaled flowers and follicles.; vs Lepidium: Cardamine has narrow pods with many seeds; Lepidium has flattened round pods with only 2 seeds.
Frequently asked questions
Is Cardamine occidentalis native to California?
Yes. Cardamine occidentalis is native to California (recorded as native).
When does Cardamine occidentalis bloom?
Cardamine occidentalis blooms Mar-May.
What plant family does Cardamine occidentalis belong to?
Cardamine occidentalis is in the Brassicaceae family, genus Cardamine.
What habitat does Cardamine occidentalis grow in?
Cardamine occidentalis grows in Wet soils, lake margins, creeks.
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.