- Rain Lilies (Zephyranthes Species) thrive exceptionally well in southern Arizona, serving as low-maintenance perennial bulbs that burst into a sudden bloom roughly three to five days following heavy monsoon rains or spikes in humidity - Their grass-like green foliage blends unobtrusively into desert xeriscapes for most of the year until late summer and early fall storms trigger their signature vibrant, crocus-like flowers ... the lily in this sketch bloomed in mid-June!