SafePlants

Tall Mountain Larkspur (Delphinium occidentale)

Delphinium occidentale, commonly known as Tall Mountain Larkspur, Duncecap Larkspur, or Western Larkspur, is a perennial plant belonging to the buttercup family (Ranunculaceae). This species is native to the western United States and is often found thriving in open woodland areas, streambanks, and moist areas.

Considerations for Pets

• This plant has been identified as potentially poisonous and is grazed on by sheep.

Considerations for Children

• This plant has been identified as potentially poisonous.

Taxonomy and Nomenclature

• Scientific Name: Delphinium occidentale Wats.
• Family: Ranunculaceae (Buttercup family)
• Genus: Delphinium
• Synonyms and alternative scientific names include:
  • Delphinium × occidentale (S. Watson) S. Watson (pro sp.)
  • Delphinium occidentale var. cucullatum (A. Nelson) R.J. Davis
  • Delphinium scopulorum ssp. occidentale
  • Delphinium scopulorum var. glaucum

Distribution and Habitat

• Delphinium occidentale occurs throughout much of the Intermountain West and Northwestern United States.
• It is often found growing along streambanks and in moist areas.
• Specific locations mentioned include Yellowstone National Park and the Nebo Loop National Scenic Byway in Utah.

Morphological Characteristics

• It is a perennial, robust forb with deep woody roots and numerous stems that can reach 2-6 feet tall.
• It blooms in the summer with blue, pale blue, or white flowers arranged in spires.

Interactions with Other Organisms

• Hummingbirds are attracted to the nectar tubes of the flowers.
• It is documented that *Plagiognathus obseurus Uhl* can be found on *Solidago*, *Delphinium occidentale*, and other low herbs

Further Information

• Additional information can be found at the RHS (Royal Horticultural Society).
• The Fire Effects Information System (FEIS) of the U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station provides data on this plant.
• Tropicos offers information on Delphinium occidentale var. cucullatum.
• Discover Life has a page about the biology, natural history, ecology, identification, and distribution of Delphinium occidentale.
• CalPhotos provides images of Delphinium occidentale.
• More information can be found within iNaturalist.org.
• The Encyclopedia of Life provides information for *Delphinium occidentale S.Wats. ex Coult.*