Bird painting artist Audubon first used the term “Lousiana flag” to refer to these beautiful big brightly coloured irises. Found across southern USA from Florida and the Carolinas to Texas, and the Mississippi valley, this group is made up of 5 species.

I. hexagona – with greeinsh
white, and purple/blue flowers, this grows to 90cm. It is less grown than the
other species and has contributed less to the development of modern hybrids.

I. Fulva – has the broadest range and is the most cool hardy, and the latest to bloom. Coloured coppery red, it has drooping falls and standards, and almost straight stems. Blooms at 45 to 60 cm high.

I. giganticaerulea – Giant blooms on 80cm stems, in a range from shades of blue/violet to white. This is the most prolific and spectacular of the group, and has some salt tolerance, growing well in coastal marshes. Blooms have upright standards and broad flaring falls, and the rhizomes are huge. Its genes dominate in most garden hybrids.

I. brevicaulis – The smallest of the group with typical zigzagging stems, and bright blue flowers blooming amid the foliage at 15 to 30 cm. This makes a good edging plant.

I. nelsoni – Botanists believe this to be of hybrid origin from I. fulva and I. giganticaerulea. The large blooms have a wide colour range from red-purple through to yellow. Height is 60 to 90 cm. This plant is limited in range to a small area around Abbeville Lousiana.

All of these species hybridised extensively in the wild, providing many interesting specimens for plant collectors. Sadly many are now endangered in their natural habitat. Louisiana species and natural hybrids were collected in the early 1900’s and grown in gardens. Hybridisation began later, still in the first half of the 20th century. Much work in developing beautiful new colours and patterns has been done here in Australia.