Calochortus is a genus of about seventy species native to North America, concentrated in the western United States, and collectively among the most beautiful and frustrating bulbs a gardener can attempt. The genus divides broadly into three groups: the open, wedge-petaled mariposas named for butterflies; the globe lilies with their downward-nodding, lantern-like blooms; and the star tulips, erect and pointed. Colors range across pink, orange, yellow, white, purple, and red, and all share the singular characteristic of hairy interiors, the texture sometimes dramatic enough to seem almost animate.

Growing them successfully demands conditions that approximate the dry, well-drained slopes and meadows of the West: full morning sun with afternoon protection, excellent drainage, and summer dryness during dormancy. They perform poorly in the humid Southeast, where summer moisture invites the bulb rot that kills them. In suitable climates, plant bulbs five inches deep in lean, gritty soil and leave them largely undisturbed. Seeds germinate readily but take several years to reach flowering size. The genus rewards those gardeners willing to study its quirks, and it offers pollinators — particularly native bees — a resource found in few other ornamentals.