Calochortus are long-lived plants for me near Portland, Oregon, given a dry summer dormancy. They require considerable depth to mature properly. Even mature plants don't necessarily flower every year. Most should not require winter chill; those that are widely available come mostly from California west of the Sierra Nevada. I find certain inland species such as C. nuttallii difficult. All of mine are in my bulb house, which has a solid roof and open, wire mesh sides, so there is no temperature control but plenty of moisture control. Cutworm can attack the plants as they emerge. I grow them in a medium that is mostly coarse sand over a lower layer of clay loam, start watering in October, and about this time I stop watering. Some of mine self-sow, and at least one has produced an attractive hybrid. Calochortus seed can remain viable in storage for many years.