What Are They?
If you came to this blog from the Zydeco Louisiana Iris Garden website and spent much time there, you probably have the answer already. Briefly, “Louisiana iris” refers to five species of closely related beardless irises native to the Eastern United States and to their many hybrids.
Each of the five species occupies a somewhat different niche in nature, and the blend of their genetic backgrounds in the hybrids has resulted in a group of plants that are adaptable to most of the country and to garden conditions that almost anyone can satisfy.
The header of this blog shows Iris giganticaerulea, which literally did come out of the swamps. It is a very tall blue species native to coastal Louisiana and extending west into Texas and east along the Mississippi coast and possibly farther. That’s it you see in the blog header. Giganticaerulea can grow to six feet tall in its habitat, which consists of open swamps and freshwater marsh. Sometimes a white form of giganticaerulea is found. That’s I. giganticaerulea you see in the header image of this blog, growing in a swamp near Napoleonville, Louisiana.
Iris fulva is smaller and typically red, although some see the color as brown, rust red or copper-colored. In truth, the color varies a bit and specimens have been found from red to orange. Yellow forms of fulva are rare but do occur. Fulva slightly overlaps the habitat of giganticaerulea, but in shallower water. And, it also grows up into the Midwest as far as Illinois and Kentucky, far away from the coastal giganticaerulea.
Iris brevicaulis is another blue (and rarely white) species, but it is the shortest of the Louisiana species, rarely exceeding 20 inches tall. And, like fulva, it grows up the Mississippi Valley into Ohio and even Ontario. Brevicaulis is found in wet areas but not in swamps or standing water. Given the contribution of brevicaulis and fulva to the Louisiana iris hybrids, their cold hardiness is easily to understand.
Iris hexagona is an East Coast species found in South Carolina, Georgia and, especially Florida. It is blue and appears to be a shorter (and later blooming) version of the tall blue giganticaerulea. Florida is full of “Louisiana” irises and they generally are all considered forms of I. hexagona, but not without some controversy.
Finally, there is one more red species, I. nelsonii, found only in a small area southeast of Abbeville, Louisiana not far from the Gulf. Nelsonii is larger than fulva and was important in hybridizing. There also are rare yellow forms of nelsonii. Nelsonii has been determined to be a population originally of hybrid origin, and its small, swampy habitat is very much endangered from agriculture.
Today’s modern Louisiana iris hybrids are derived from these species and the natural hybrids found in the wild. The story of these irises, including and lots of pictures, is detailed in a the species pages on the Zydeco site.