It is not known how long plants live, but probably at least 10 years.

In contrast to typical pollinators for the genus Delphinium, which are insects, potential pollinators for yellow larkspur are Allen’s hummingbirds, which have been observed visiting the flowers. In addition, the flower shape and sucrose-dominated nectar are consistent with characteristics of species that are typically pollinated by hummingbirds. Bumblebees have also been observed visiting yellow larkspur flowers in a nursery setting. Yellow larkspur is self-compatible, but visitation by pollinators improves seed set.

Yellow larkspur inhabits coastal prairie and coastal scrub, which typically have no overstory, at elevations ranging from sea level to about 300 feet within northwestern Marin and southwestern Sonoma counties, California. The species occurs on moderate to steep slopes with evidence of some level of disturbance nearby, including landslides of various ages. Typical soil types supporting yellow larkspur derive from sandstone or shale and share qualities of rapid runoff and high erosion potential. The most recently documented populations tend to grow on north-facing slopes in canyon complexes with steep sides. Coastal fog keeps summers relatively cool and winters relatively warm compared to inland habitats.  

Yellow larkspur grows from fibrous roots to 22 inches tall. The leaves are mostly basal, fleshy and green at the time of flowering, which occurs from March to May. The flowers are cornucopia shaped with five conspicuous bright yellow sepals, with the posterior sepal elongated into a spur. The inconspicuous petals occur in two pairs: the upper petals are narrow and unlobed and the lower petals are oblong to ovate. The fruit is a follicle.