Tall Mountain Larkspur
Delphinium X occidentale (S. Wats.) S. Wats.
Family: Ranunculaceae, Buttercup
Genus: Delphinium
Other names: duncecap larkspur
Nomenclature: occidentale = western
Nativity / Invasiveness: Montana native plant
Poisonous plant
No medicinal data

General: robust, erect perennial from woody, thickened rootstocks. Stems several, 70-200 cm tall, hollow, simple, mostly with some bluish cast, usually hairless below and crisp-short-hairy to glandular-hairy in the flower cluster.

Leaves: alternate, stalked and slightly reduced upward, the basal and lower stem leaves often withering. Blades 5-15 cm broad, cleft to the base into 3 main lobes, the side lobes each again divided not so deeply into 2 main segments. All 5 segments wedge-shaped, irregularly cleft or lobed or toothed.

Flowers: pale blue to whitish, with 5 sepals around 4 small petals, many in tall, narrow clusters up to 35 cm long, closely flowered, with flower stalks shorter to longer than the spur. Calyx usually finely crisp-hairy, sometimes glandular-hairy, deep bluish-purple to nearly white, often streaked with white, the side sepals 9-15 mm long, rounded to pointed. Spur 10-15 mm long, longer than the upper sepal. Lower petals pale to deep blue, the upper nearly white to pale blue. Late June-August.

Fruits: erect follicles, 10-16 mm long, short-hairy to glandular. Seeds about 2-2.5 mm long, wing-angled.


Along streambanks and meadowland or on moist talus slopes, montane to subalpine zones, in w. and c. parts of MT. Also from n.e. OR to CO.
Poisonous Properties

All larkspurs are highly toxic and may be fatal if eaten. Symptoms after ingestion include burning of lips and mouth, numbness of throat, intense vomiting and diarrhea, muscular weakness and spasms, weak pulse, paralysis of the respiratory system, and convulsions. The toxic principles are the alkaloids delphinine and ajacine among others. Toxicity decreases as the plants age, but the seeds are very poisonous. Many cattle have been poisoned by larkspurs.

Recommended Suppliers for Your Own Plant Garden

Advertising Disclosure: Montana Plant Life may be compensated in exchange for featured placement of certain sponsored products and services, or visitors clicking on links posted on this website.
Save on Seeds
Copyright © Montana.Plant-Life.org