When European botanists/explorers first encountered plants in the Americas, they often graced them with scientific names that denoted their provenance: epithets such as americana, virginiana, caroliniana, or canadensis were appended to the name of the genus. But how did the American genus Zephyranthes earn its name?
At least since the 17th century, the word “zephyr” has denoted a gentle breeze. An earlier meaning, coming from the west, traces back to the Greek, zephuros, god of the west wind. Although countless plant species indeed came to Europe from the West, i.e. the Americas, the genus Zephyranthes is the only one I’m aware of that honors the Greek god.
With seventy-some species, Zephyranthes is one of the plant genera referred to as either rain lilies, fairy lilies, magic lilies or zephyr lilies. (I’ve only ever heard the first term used.) As a common name, rain lily can also refer to the closely-related genus Habranthus, as well as to the former genus Cooperia. The latter name is no longer valid, as taxonomists would say, and those plants have now been incorporated into the genus Zephyranthes. Just as well, since Cooperia is also the name of an intestinal parasite.
Nomenclature aside, all the rain lilies are herbaceous perennials growing from bulbs. Foliage is slender and grass-like, often only about 6 inches long, with the flower stalks achieving a similar height. The small tubular flowers range in color from white to pink, then on to yellow and orange, but hybridization has produced attractive blends of the basic hues. As the name implies, many rain lilies are known for producing their summer blooms a few days after a rain.
But why do rain lilies seem to bloom only following rains? Various sources state that they flower consistently even after brief rains, but won’t respond to watering. I couldn’t find a definitive answer to this question—one can spend only so much time on Wikipedia before cobwebs begin to form—but there were a couple of hypotheses.
One source said the key to flowering was the combination of lower temperatures and greater moisture. To put this in context, you have to picture the native habitat of some of the rain lily species, in many cases either a tropical savanna with a pronounced dry season, or a prairie with long dry periods interspersed with occasional downpours. In these situations, a rain lily may be nearly dormant for weeks or months, springing to life following a rain. The rains would not only provide water, but will lower the temperature for a period. The plant takes advantage of this and quickly flowers and sets seed. Artificial irrigation provides the water part of the equation, but wouldn’t furnish the cloudiness and lower temperatures. One more idea regarding natural rains: they’re typically associated with a drop in atmospheric pressure, and somehow rain lilies respond to that.
Among the many Zephyranthes species, one is native to Virginia, Z. atamasca., the Atamasco Lily. Found in bottom lands from the lower Eastern Shore, south to Florida and west to Mississippi, the Atamasco Lily is native only to the southern part of Virginia. Larger than many rain lilies, with three-inch-wide flowers atop 10” stems, its white flowers light up the dark forest understory in mid-April. Given their native habitat, Atamascos have somewhat different growing requirements than other rain lilies. Deciduous shade is fine, but water should be consistent through most of the growing season.
Picking a rain lily for your garden is largely a matter of color preference, along with considering the plant’s hardiness. Many rain lilies “officially” are rated as hardy only to zone 7b, i.e. about 5 degrees warmer on average than Albemarle County, but plants don’t read, so feel free to try most in your garden. Just one example of differing opinions on hardiness: Z. carinata, commonly called simply Pink Rain Lily, is often listed as hardy to zone 8. Yet writer Elizabeth Lawrence, who gardened in Raleigh and Charlotte, wrote that is “one of the hardiest…said to winter safely in Philadelphia”—despite being native to Central America. Four-inch-wide deep pink flowers make quite a statement in a mass planting.
A brief mention of Habranthus, the “other” rain lily genus, and another member of the Amaryllis family: unlike Zephyranthes, Habranthus flowers are slightly asymmetrical and face outward. I’ve grown what I believe to be H. robusta for several years and found it to be totally hardy.
A hint at the great variety of rain lily cultivars can be found on the website of Plant Delights Nursery. Although offering only 8 varieties for sale at this time—four sold out earlier in the season—the website provides hundreds of pictures, featuring dozens of varieties. (When on the Zephyranthes page, scroll down toward the bottom and click on “Check out our Rain Lily photo gallery.”) Proprietor Tony Avent told me via email that “we cycle the rain lilies in and out of stock based on our available stock and past sales history,” so you might find something different later in the year.
Except for the shade-dwelling Atamasco lily, rain lilies prefer full-to-part-sun and good drainage. As small plants, you need a substantial number to stand out in the garden, although growing a few in a container can also make a statement. Keep them away from chewing pets, since both the foliage and bulbs are considered toxic. I’m not sure my local bunnies got the message about toxicity, however.
Sharp-eyed readers may have noticed that the top picture in July’s column was mislabeled. It should have read “Wild Ginger” rather than “Wild Lily.” Sorry about the mix-up.