Understanding Louisiana Iris Part 4 I. nelsonii

Understanding Louisiana Iris Part 4 I. nelsonii

                                                                    By Joseph Musacchia

  I. nelsonii is the most recently named Louisiana iris species. It was named by Randolph in 1966 for Dr. Ira Nelson, Professor of Horticulture, Southwestern Louisiana Institute, now the University of Louisiana at Lafayette.  

  I. nelsonii was a sensation among Louisiana iris enthusiasts after it was "discovered" around 1938 by W. B. MacMillan. Restricted to a small area Southeast of Abbeville, Louisiana, they were commonly called the "Abbeville Reds," or occasionally "Super Fulvas."  Because of their size and color, they were used extensively in early hybridizing. 

I. nelsonii  'Young's Coulee'
Collected by Benny Trahan

 The comparison to I. fulva was due to color, and the superlative "super" reflected their size.  In their native swamp habitat, they grow considerably taller and have larger flowers than Iris fulva, although they resemble I. fulva with the red and yellow underlay. A few yellow forms were found in the relatively small area of its range.

‘Butead’s Gift’ collected by Benny.

A nice collected red.

  Unlike fulva,however, and much more like I. giganticaerulea, the Abbeville reds were found in shallow water in cypress swamps.  I. Fulva is more typically an inhabitant of wet sloughs and roadside ditches; wet areas to be sure, but not in the swamp per se.

Just southwest of Lafayette
Louisiana

The  I. nelsonii habitat is restricted to a few square miles of cypress/tupelo swamp.  Due to the environmental impacts on the area, it is seriously endangered.  Through the efforts of the Louisiana Department of Wildlife and Fisheries, a population of nelsoniis have been moved to the Palmetto State Park a few miles away, where they can be protected. 

  Past research determined that I. nelsonii is a species of hybrid origin, with traces of fulva, giganticaerulea and brevicaulis in its background.   It is presumed that the I. nelsonii environment was relatively isolated and, after unknown years of inbreeding, the population stabilized to create the species. Additional research is ongoing and a fuller understanding of the origins of I. nelsonii may emerge.  Whatever I. nelsonii's origins, it was a fascinating find and was exceedingly important in developing the modern cultivars of Louisiana iris available today.

Closed loop styles

Darker center lines on the
standards and falls

 Some unique traits of I. nelsonii include the closed loop of the styles which almost encloses the anther; the darker center lines on the standards and falls; and the pendent form. It has little or no signal. It grows in standing water in the swamps and so needs lots of water in the garden. It can also handle more shade than most LA’s. 

"I. nelsonii"   Growing in 
“Young's Coulee”

   I. nelsonii  adds a lot to the gene pool for hybridizing. Characteristics it contributes include taller, stronger stalks, more color, ability to grow in shadier areas, better root structure to hold up taller stalks, and  other unique features. 

  In up coming articles I will show how the unique features of these four species of Louisiana iris make up the the modern cultivars. Hopefully, this will help you make better decisions on what will grow in different areas of your garden. Or, why some cultivars won't grow/bloom in your garden.