Delphinium trolliifolium
Cow poison, poison larkspur, Poison Larkspur
(c) Alex Abair, some rights reserved (CC BY), uploaded by Alex Abair · licence
Family: Ranunculaceae · Type: Herb · Native
Delphinium trolliifolium (Cow poison) is a native California herb in the Ranunculaceae family, recognized by North Coast distribution with broad irregularly cut leaf lobes and long fruits.
Cow poison is a California native perennial found in northern coastal California and northern Coast Ranges in oak woodland and coastal chaparral at elevations of 30 to 1,100 meters. Flowering from April to June, this plant produces blue to purple flowers with deeply lobed sepals and a distinctive curved spur. Growing 60 to 120 centimeters tall with stems that are glabrous to slightly hairy and typically narrower at the base, it develops an intricate branching structure. Its leaves feature multiple lobes more than 1 centimeter wide with sharply and irregularly cut tips, creating a distinctive, complex leaf shape. The plant produces elongated fruits 15 to 34 millimeters long that are notably curved and generally more than four times longer than wide.
Identification and appearance
Key characters: 8 sympatric species; North Coast distribution with broad irregularly cut leaf lobes and long fruits
Habitat and range
Habitat: Oak woodland, coastal chaparral
Elevation: 30-1100 m
Outside California: Oregon
Bloom period
Delphinium trolliifolium blooms Apr-Jun.
How to tell it apart
vs Lupinus: Delphinium has backward-pointing spurs on flowers; Lupinus has pea-family flowers with banner-wing-keel structure.; vs Geranium: Delphinium has spurred bilateral flowers; Geranium has radially symmetric 5-petaled flowers with no spur.; vs Epilobium: Delphinium has spurred flowers and palmately divided leaves; Epilobium has unspurred 4-petaled flowers and simple or opposite leaves.; vs Aquilegia: Delphinium has a single spur per flower; Aquilegia has 5 spurs radiating from the center.; vs Aconitum: Delphinium has an open spur with visible stamens; Aconitum has a closed hood hiding the stamens.
Frequently asked questions
Is Delphinium trolliifolium native to California?
Yes. Delphinium trolliifolium is native to California (recorded as native).
When does Delphinium trolliifolium bloom?
Delphinium trolliifolium blooms Apr-Jun.
What plant family does Delphinium trolliifolium belong to?
Delphinium trolliifolium is in the Ranunculaceae family, genus Delphinium.
What habitat does Delphinium trolliifolium grow in?
Delphinium trolliifolium grows in Oak woodland, coastal chaparral.
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.