Member Essay

Louisiana Iris

There are at least 5 species that make up the Hexagona Series that we call Louisiana iris. The "Hex" in the name refers to the 6 prominent ribs on the seed pods.


I. brevicaulis
Color range is pale blue through blue-violet, shorter, blue-green foliage and more disease-resistant foliage

I. fulva
Smaller flowers ranging in color from brick red, orange, red and copper

I. giganticaerula
Tall, up to 6' bloom stalks. In shades of blue or white with yellow signals

I. hexagonae
Lilac, medium blue to deep purple violet

I. nelsonii
Source of the Abbeville reds

Where is home: For the species the range is Texas across to the Florida panhandle. Then up the Mississippi River valley to the mouth of the Ohio River valley. Because their seed pods float well on water there is a theory that these species were found once in the American Midwest then dispersed south on the Mississippi River.

Advantages: Louisiana irises have the broadest color range of any iris series including red from the Abbeville reds. Diversity in form is more extensive than the color choices. Form is referring to the falls. They may be: flaring, semi-flaring, pendant, recurved, open and overlapping.

Where we like to grow: In acid soil first and foremost. One way to get this is to add agricultural sulfur in the ratio of 1 to 2 pounds per 100 square feet of garden. We like moisture; not to the point of growing in water but next to it is fine. Heavy clay soil is okay since it helps retain moisture. Two feedings of manure or azalea/rhododendron food per year are needed. The first time when foliage is starting to turn green and again after blooming. In the Northwest give them as much sun as possible.

Hybridizing trends: The emphasis has been to increase bloom size so everything is in the 3" to 7" range. California has surpassed Louisiana as the place for hybridizersóJoe Ghio and the late Ben Hager to name two. There is a need to improve the quality of smaller blooming varieties.

Awards: The Mary Swords DeBaillon Medal is the top AIS award for Louisiana iris. It is named for a woman who collected the native species iris. The 1999 winner was PROFESSOR NEIL from J. Mertweiller of Louisiana. There were two runners-up, COUPD'ETAT and C'EST FANTASTIQUE both from Mary Dunn.

Contributed by Dwayne Booth, February 2000