Bot. Gaz. 12: 53. 1887
Phenology: Flowering late spring–early summer.
Habitat: Talus, cold desert scrub, often growing up through shrubs, low places where snow collects
Elevation: 1300-2000 m
Calif., Idaho, Mont., Nev., Oreg., Utah.
In much of its range Delphinium andersonii hybridizes occasionally with members of the D. nuttallianum complex and apparently with D. parishii in at least one site in California. These three taxa, with D. scaposum, form an interesting group in that they appear to be ecological replacements for one another, with D. parishii occupying arid, hot deserts to the south and southwest, D. andersonii growing in cooler, higher latitude and altitude deserts farther north, D. scaposum in cool deserts farther east, and D. nuttallianum at higher elevations in much of the geographic range of the other three species. Delphinium andersonii is often mistaken for D. nuttallianum. Most individuals of D. andersonii (roots much larger and more fibrous; stems solidly attached to roots; fruits long, narrow, erect; inflorescences usually longer and narrower at base; and pedicel sigmoid) can easily be distinguished from D. nuttallianum (roots smaller and not fibrous; stems tenuously attached to roots; fruits shorter, proportionally thicker, spreading; inflorescences relatively shorter and wider at base; and pedicel nearly straight).
Although roots of Delphinium andersonii are quite similar to those of D. antoninum, the two taxa may be readily distinguished by most features that separate D. nuttallianum from D. andersonii. The name Delphinium menziesii was misapplied to D. andersonii by S. Watson.