Louisiana Iris: A Southern Floral Icon

Provocative blooms

The flowers are what make the plant so provocative. The three petals and three sepals, often similar in color, are organized as two alternating whorls. A whorl is a biological term that refers to a set of petals going around the vertical axis of a flower. Each can range from upright or flaring to even arching or pendant. Furthermore, the flower may be augmented with an unusual third whorl: either flared styles (a style is the elongated part of the female pistil) or petaloids (extra petals) that vary in length and often sport elaborate crests. Double and semidouble flowers also are produced.

All floral parts are “beardless.” This means that the inner midline of each petal lacks the upright hairs or “beards” characteristic of most European or Asiatic varieties – the species most commonly marketed in plant catalogues.

Finally, the colors of Louisianas eclipse those of all other varieties. The palette ranges from pure white and yellow to blue, lavender and violet, as well as orange, rust and red. Appropriately, in Greek mythology, Iris was the female deity who transported messages between the Earth and the heavens. She was symbolized by the rainbow and referred to as “Goddess of the Rainbow.”

Upping the ante, in 1973, a retired research chemist, the late Joseph K. Mertzewiller, discovered how to give Louisiana Irises an auspicious genetic makeover. He accomplished this by exposing seeds to colchicine, a poisonous alkaloid originally extracted from the roots and seeds of the autumn Crocus or Meadow Saffron plant.

In certain plants, colchicine interferes with basic cell division, resulting in genetic anomalies called tetraploids (simply put, the plants have double the amount of genetic material – think chromosomes and DNA). More than 30 true-breeding tetraploid varieties of Louisiana Irises have been created; all produce flowers that are extraordinary in both form and color, and all are registered and marketed.

Gardeners might presume that these plants, which are native to the topsy-turvy wetlands of the Deep South, would prove finicky to cultivate elsewhere. Not so. The severe conditions of the natural habitat have genetically predisposed Louisianas for an unusually high tolerance to diverse environments. For good measure, individual plants are relatively resistant to pests and diseases. As a result, these hard-knock irises are prized and cultivated successfully in private and public gardens throughout the world. So, although Louisiana loses more wetlands each year than any other state, we natives know that the future of our regal – and natural – fleur-de-lis is secure.