Cookie Cutter Moon Rain Lily. If you have been disappointed in the vigor of some Rain Lilies as I have, this is one that over-performs. It is extremely vigorous. The Pacific Bulb Society tells us that "'Cookie Cutter Moon' is a large, white flowered, naturally occurring hybrid of unknown ancestry found in the state of Tamaulipas, Mexico and introduced by Yucca Do Nursery." It was found in 1996 near Zephyranthes clintae and Zephyranthes traubii, so these two species may be the source of its parentage. It flowers from early summer into fall and is stimulated to flower by a good shower of rain. Where we grow it with daily overhead irrigation, it doesn't stop flowering. Plant it so that it gets part to full sun for best bloom. The first picture is courtesy of the Pacific Bulb Society.