Cooperia is a genus of tender herbaceous perennials native to South America and the southern reaches of North America. They are closely related to Zephyranthes and Habranthus, all members of the Amaryllidaceae, or Amaryllis family. All three genera are commonly known as rain lilies because of their propensity for blooming after a rain. Cooperia blooms in summer and fall.
Cooperia is distinguishable from the more famous rain lily genus, Zephyranthes, by its fragrance similar to primroses, its white or yellow pollen, and its tolerance for droughty and desert conditions (Howard 2001:54). It also tends to be night-blooming (Ogden 1994:11).
Cross-generic hybrids have been successfully created with both Zephyranthes (× Cooperanthes) and Habranthus (× Cooperanthus) (Ogden 1994:11, Howard 2001:54).
- Fellers, John D. "A Passion for Rainlilies: Cooperia, Habranthus, and Zephyranthes." Herbertia v51, 1996, pp 78-112.
- Howard, Thad M. Bulbs for Warm Climates. Austin, TX: University of Texas Press, 2001, pp 53; 54-56.
- Ogden, Scott. Garden Bulbs for the South. Dallas, TX: Taylor Publishing Co., 1994, pp 5-27.