Allium sanbornii is a large onion restricted to the Sierra Nevada and southern Cascade foothills of California. It is only found on serpentine outcrops. Photos by Nhu Nguyen. Seeds sprout readily and this species is actually one of the easier California onions to grow. It is one of the latest blooming species (around July) when most other native bulbs have already gone into dormancy. It requires a very dry summer dormancy period. The photos below were taken by Nhu Nguyen. Photos 1-3 were of plants growing at the Tilden Botanic Garden.
The photos below were taken by Nhu Nguyen of a white form of this species.