The Louisiana iris species Iris fulva is a wonder and a surprise. Few expect to encounter wild red irises, but they are out there and not just in Louisiana.
Fulva is not impressive in flower size, but it is unique in form, and its color is unforgettable in early spring when found along a wet roadside or bordering a river, stream, or bayou. It has been described variously as beautiful, interesting, and odd.
Iris fulva occupies a singular place in the history of the Louisiana irises. It was the second species in the group to be formally named, based on a specimen collected in 1811 near the Mississippi River in New Orleans by John Lyon, a Scottish-born plant explorer. Lyon sent the specimen to England, where John Bellenden Ker-Gawler recognized it as distinct and published both a description and an illustration in Curtis’s Botanical Magazine in 1812.
At the time, Iris fulva caused a sensation. Among several hundred known iris species, it was the only red-flowered iris, a novelty that immediately set it apart.
In 1821, John James Audubon painted a watercolor of the Northern Parula Warbler, depicting two birds perched on an iris he called a “Louisiana flag.” The botanical background ‒ later identified as Iris fulva ‒ was painted by Audubon’s assistant, Joseph Mason. This image is widely credited with establishing the enduring association of the term “Louisiana” with this distinctive group of irises.
The modern appreciation of Iris fulva owes much to the work of John Kunkel Small, whose research in the 1920s and 1930s brought the Louisiana irises out of relative botanical obscurity and into horticultural prominence. Under Small’s direction, the New York Botanical Garden commissioned a series of iris paintings by Mary Eaton, documenting both newly proposed species and those already recognized. Eaton’s 1927 painting of Iris fulva, published in Addisonia, remains one of the most botanically complete and accurate visual records of the species.
Together, these three historical images portray Iris fulva in its most common color form, yet a broader survey of collected specimens reveals remarkable variation, underscoring the species’ genetic richness and partly accounting for the remarkable color range of the Louisiana iris cultivars.
Fulva is one of two predominantly red iris species. The other, I. nelsonii, was only designated as a species in 1966, and probably evolved from fulva. The two have been the principal contributors of red and related colors in modern Louisiana iris hybrids.
As seen in the gallery, not all fulvas are red. “Copper iris” is a common but unfortunate nickname since fulvas are mostly rust red or reddish orange. Copper takes on different hues under varying conditions, but some find that a copper penny resembles the color of fulvas. Some see it as brown.
Yellow is a rare recessive color encountered now and then, and exciting to find. Yellow forms can be a bright, clear yellow or more of a butterscotch color.
The range of colors in the gallery are not representative of what you will see along Louisiana roadsides or near bayous. The rust-red shades are predominant, but the unusual colors in the gallery reflect the genetic diversity that shows itself now and then.
Of the nearly 400 species of irises worldwide, only fulva and nelsonii approach true red in nature. A few species in the bearded iris group are reddish-purple.
The flower of fulva is relatively small, 3-4 inches across, and frequently, all the flower parts droop. Flaring rather than pendant forms also occur, as the gallery shows.
The specimens with drooping sepals and petals probably account for those who find the flowers “odd.”
Fulvas have typical strap-like iris foliage. The bloom stalks are taller than the foliage, usually 24 – 30″. The bloom stalks often branch and have two flowers at some bloom nodes, an excellent characteristic that has been imparted to many hybrids.
Fulvas appear relatively early in the bloom season. In Louisiana, bloom might begin in mid-March and last into mid-April. Depending on the weather, these dates can shift a week or so in either direction. The season occurs later in the northern parts of its range.
Fulvas do not make as much of a splash in the garden as the larger, more substantial flowers of hybrids or even some of the species, like giganticaerulea. Nonetheless, fulvas are unique and charming wildflowers, with no need for apology when compared to other plants. They are the real deal.
Fulva occurs in alluvial soils near rivers, streams, and bayous. It ranges far up the Mississippi Valley into Missouri, Illinois, and Ohio, and occurs in the deltas of rivers south to the Gulf, including the Arkansas, Ouachita, Atchafalaya, and Mississippi Rivers.
Wetland conditions in Louisiana provide extensive habitat for I. fulva, and the number of plants dwarfs those found in other states. This concentration also placed the irises in proximity with other species, particularly I. giganticaerulea, resulting in “hybrid zones” where the offspring of the two species created a base from which many modern Louisiana iris cultivars were developed.
Fulva genes are one of the principal reasons for the hardiness and wide color variation of Louisiana iris hybrids grown across most of the country.
Parish (county) level incidence of I. fulva’, bright green. Yellow indicates uncommon. Biota of North America Program (BONAP)
A view of a field of butterweed with fulvas and spider lily in a roadside ditch.
More information on Iris fulva:
