Saturday, January 23, 2010

Atamasco Rain-lily - Zephyranthes atamasca

Florida is home to two distinct varieties of Atamasco rain-lily (Zephyranthes atamasca).  While some taxonomists separate the two into different species, I will side this time with the "lumpers" - and hope I am wrong because I am a "splitter" at heart.  Basic Atamasco rain-lily (Z. atamasca var. atamasca) has leaves that are at least twice as wide as those of Treat's rain-lily (Z. atamasca var. treatiae), but otherwise they are identical.  Atamasca rain-lily occurs throughout the northern two-thirds of Florida and in much of the Southeastern Coastal Plain.  In Florida, it is considered a state threatened species.
All of our native rain-lilies require open habitats and reasonable moisture to prosper so they are most common to open flatwoods, mowed roadsides (and similar types of such habitats), and pastures.  In these areas, it often goes unnoticed when not in bloom as it consists of linear grass-like leaves that often blend into the surrounding vegetation.  But, when in bloom it becomes spectacular - especially if growing in mass. 
Atamasco rain-lily is a perennial evergreen (at least in central Florida) member of the lily family.  As such, it originates from a bulb, and this bulb produces bulblets off its outer edge over time which form new plants.  Eventually, Atamasco rain-lily forms colonies around each plant consisting of many individuals.  These are easy to subdivide and transplant to new areas or they can be left alone as a mass planting.
Basic Atamasco rain-lily has leaves that are about 1/4 inch wide while those of Treat's rain-lily rarely exceed 1/8 inches.  Both can be as long as 18 inches and the plants form nice mounds of leaves when not in bloom.
It's the blooms which make this species a favorite wildflower, however.  Though individual flowers only last a couple of days, they are 3-4 inches long and either pure glistening white or with a flush of pink - as in the photo above.  They are held 6-18 inches above the leaf mass. 
As its common name implies, flowering occurs only after a spring or early summer rain shower.  The day after a measureable rain, a rose-pink bud becomes visible within the basal leaves and by the second (or third) day, the flowers are open.  Although flowering may occur sporadically at other times, nearly all blooming takes place during late spring or summer and only lasts for about a month.  Flowers are sometimes produced in succession, but individual plants will flower after each rain event during this time period. Once the plants have gone through this cycle of flowering, additional rains later in the season rarely trigger more.
Rain-lilies produce large numbers of seed and also propagate themselves this way.  I have found them easy to grow from seed and it allows me to produce more plants without the trauma of digging them out of the ground to remove the side bulbs.  Pollination mostly comes from bees.
Treat's rain-lily is very similar in appearance to Simpson's rain-lily, described below.  The best way to keep the two species separate is by looking at the length of the female part of the flower (the style) compared to where the pollen-producing parts are (the anthers).  In both forms of Atamasco rain-lily, the female portion of the flower is nearly twice as long and sticks well out beyond the anthers.  In Simpson's rain-lily, they are the same length.
As should be expected, Atamasco rain-lilies are commonly propagated by commercial sources and are widely available to the home gardener.  Just be careful that you are getting a native rain-lily, however, instead of one of the many non-natives that are also widely sold.  Rain-lilies are extremely hardy and durable.  They can withstand long periods of drought as well as great amounts of moisture.  They also have a wide tolerance for amounts of sunlight.  Just don't try to use them in deep excessively well-drained sands or in deep shade.  I like rain lilies in mass, but they also do well in mixed plantings or planted in lawns.  They can be mowed regularly with no real damage as long as they are not cropped right to ground level. Just don't mow them for several days after a rain or you will miss the reason you added them.

7 comments:

  1. I would like to see a price list on the rain lilies, which would be resold in a Master Gardener's fall bulb sale, zone 7b.

    This site has been useful, since I was only aware of the pink and white, not the other colors.

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  2. There's another white Florida native rain lily.
    Is cream in color and it blooms early summer!
    Very few flowers.... I've seen it in the area of Port Saint Lucie, Florida
    I am trying to dig out one of those bulbs... Maybe next year hopefully!
    I have passion for rain lilies and more passion for the ones that blooms in late spring...
    Unstable weather conditions in Florida makes it hard to bloom!
    I brought a spring blooming pure white rainlily from central america and I only saw it bloom here in Florida 4 years ago... That's because we didn't have enogh rain in past springs!

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  3. It's not the rain, but the thunderstorms that make them bloom. When it thunders, nitrogen is released and brought down in the rain storm. That is when they flower. I have seen yellow ones in my yard as well, which bloom very rarely.

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  4. Thanks for your input, but its not just nitrogen either - or fertilizing them would cause the plants to bloom. They have a distinct blooming season and they bloom each time it rains heavily during that window. The same types of rain do not trigger them to produce flowers outside their blooming season.
    Rain lilies come in a wide variety of colors and styles - but these, like the yellow-flowered species, are not native. Pretty plants regardless.

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    1. I have both Habranthus & Zephyrs. Many colors, white, pink, yellow, orange and purple and many shades in-between. I lives in coastal central. Florida. The bulbs come from Florida, Mexico, Texas, Bahamas, Argentina & Brazil. They start blooming in late Apr/May and continue til late fall.

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  5. There's something very mysterious about rain lilies also. You can water your garden all you want with a hose, you might even see one or two rain lilies, but they don't really appear until after the first couple of big rain storms. Then they come in waves. I even have a couple blooming by my front door right now.

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