Red Sierra Onion Allium obtusum
Red Sierra Onion is a perennial wildflower native to the lower 48 states. It blooms Apr – Aug.
More about this plant
Allium obtusum is a species of wild onion known by the common name red Sierra onion or subalpine onion. It is native to eastern California and western Nevada. It is a common plant in the granite foothills and mountains of the Sierra Nevada and southern Cascade Range, from Tulare County to Siskiyou County, from elevations of 800 to 3,500 metres. In Nevada, it is reported only from Washoe County in the northwestern part of the state. Wikipedia →
Growing & care
USDA PLANTS · TRY- Hardiness
- ≥ zone 10 derived from its U.S. range
- Lifespan
- Perennial
- Flower colour
- Pink AI AI image-analysis of community-science photos (~87% expert agreement) — not a botanical record
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~21 caterpillar species
Allium supports ~21 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 Allium in North America, including:
+ 8 more species → ↑ show fewer
Wildlife & visitors 2 nectaring
Open records of who else uses Red Sierra Onion — a generalist food-web signal, kept separate from the keystone Ecological Value.
2 adult butterfly & moth species are recorded nectaring at its flowers:
Related plants
More Allium →
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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