

Little Larkspur Delphinium bicolor
Little Larkspur is a perennial wildflower native to Canada and the lower 48 states. It blooms May – Jul.
More about this plant
Delphinium bicolour is a species of larkspur known as little larkspur and low larkspur. It is native to northwestern North America from British Columbia to South Dakota, where it grows in mountain forests and foothill scrub and prairie. This is a perennial herb growing from a thickly branching root system. It produces solitary stems to 40 centimetres (16 in) in height and green with reddish bases. Most of the leaves are low on the stem and grow on short petioles. They are several centimeters long with many rounded lobes. The small inflorescence holds a few large flowers per stem. The flower has dark purple-blue sepals each about 2 centimeters long and a spur of 1 to 2 centimeters. The plant is poisonous to cattle, less so to sheep, and it is occasionally eaten by various species of wild cervids. Wikipedia →
Growing & care
USDA PLANTS · TRY- Hardiness
- ≥ zone 4 derived from its U.S. range
- Lifespan
- Perennial
- Flower colour
- Purple AI AI image-analysis of community-science photos (~87% expert agreement) — not a botanical record
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~10 caterpillar species
Delphinium supports ~10 caterpillar species.
Native butterfly & moth caterpillars are the base of the terrestrial food web — most songbirds rear their young almost entirely on them. As a host for native Lepidoptera this is a moderate genus.
Recorded feeding on Delphinium in North America, including:
+ 8 more species → ↑ show fewer
Across 56 U.S. vegetation-survey plots that recorded Little Larkspur, these catalog species turned up most often in the same plot — a real field co-occurrence signal, not a planting prescription.
How we know this (2) Methods & honest limits
We take the plant’s U.S. county range and look up each county’s long-term climate, then summarise: native rainfall = the median annual rainfall across its counties; heat tolerance = the warm end (90th percentile) of average temperature across its range (mirroring how our cold-hardiness floor uses an extreme). Counties + medians blunt the roadside/observer bias that makes point-level climate unreliable. Needs at least five placeable counties.
Honest limits: A realized, sampling-biased niche (where it has been recorded, not its physiological optimum), and county climate is coarse — large Western counties span deserts and mountains. Derived guide, never a measured fact.
McKenzie et al. assigned each species a flower colour with a GPT-4V vision model over iNaturalist photos. We use the confident tier plus a separately-labelled lower-confidence top-up (mostly inconspicuous green/brown flowers), and render it as a small tint — never as an asserted fact, and kept out of the written synopsis.
Honest limits: AI image inference (~87% expert agreement on the confident tier); a decorative, confidence-tiered indicator, not a measured trait.
Sources for this entry (17) Open & cited
Cite this page Open data, please attribute
PlantKey’s data is open under CC BY-SA 4.0 — free to reuse and adapt, with attribution and the same licence. Photos keep their own per-image licence + credit (see Sources above).
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