The "Open Form" of Louisiana Irises

by Ron Killingsworth

Louisiana irises have a large variety of sizes and flower forms.  Unlike some of the species of irises, Louisiana irises are not divided into groups by size of the plant, such as Tall Bearded, Medium Bearded, Border Bearded, etc.  Louisiana irises can range from 10 inches (or smaller) to 50 inches (have seen plenty taller than that!).  The diversity of color in the bloom of Louisiana irises is another subject.  The name “Iris” is derived from a Greek word meaning “rainbow” and Louisiana irises certainly come in a “rainbow” of colors. I will try to do some follow up articles about the amazing colors of Louisiana irises.

Publications will generally list the following flower forms for Louisiana irises but I think the list is not all inclusive.  Upright Standards, Semi-flaring to Flat, Pendant Form, Umbrella Pendant Form, Recurved, Open Form, Full Overlapping, Ruffled, Semi-double.  There is also a double form and a “cartwheel” form.  I have been told there is a difference between a “cartwheel” and a “double” but the science is beyond my comprehension. Of course some blooms are a combination of these forms.  You can easily find an iris with the open form that also has upright standards.

Official Louisiana irises flower forms

The purpose of this “blog” is to discuss the open form of Louisiana irises and I have therefore not bothered trying to give the names of all the irises used in this discussion.

 

Still open form but very close to being "semi-flaring"

The species of Louisiana irises, still to be found in the wild, almost always have the "spidery" open form.  As they were hybridized, over the years, the various other flower forms developed.

This is a good example of the open form but notice it also has upright standards

I believe this is probably the white form of iris.giganticaerulea.  This is a classic example of the up-right standards form with the falls falling down and the stands standing up.  But, it is also the open form because of the size of the petals and distance between them.

This is 'Dixie Deb' by Frank Chowning registered in 1950 so it is not surprising that it has the open form.  This iris is very well known and still wins awards at shows.

Probably another example of the white iris.giganticaerulea.  Many collectors during the early 1930-1950 era collected the species from their native habitat and actually registered and named them.

While it certainly resembles the one above, it is a difference iris.  This one is also the upright standards form while still being the open form.  The falls are larger than the one above.

This flower is just between the open form and the semi-flaring form.  The falls and standards all lie flat out while the style arms often stand up.

Another beautiful example of an older Louisiana iris, possibly species, with the upright standards and the falling falls, yet still the open form.

I would suspect this iris was hybridized in the 40's or 50's, based on the size of the petals and the signal.  I could be wrong!  It is almost into the semi-flaring and almost flat with the style arms standing up.

A very open iris flower with a nice color.  Once again the stands are standing up and the falls are tending to fall down although not all the way down like most irises with the upright standards

A pretty white/yellow flower that is almost flat in shape.  Still the open form but approaching semi-flaring

A very pretty blue iris with nice signals.  I would certainly classify this as the upright standards form but because the petals are small, it still has the open form.

While this flower has the open form, it is almost in the pendant form, where the falls and standards all fall down.  Isn't that a game we played as children?

This flower certainly has a pleasing color.  It was not unusual to find colors like this growing in the wild of south Louisiana.  I do not know if this is species or a registered iris, I simply do not know it and can't remember where I took the picture.

A pretty white iris with really green style arms.  Is it the open form or the upright standards form. Yes, it is.

A very pretty yellow.  Much larger than the 'Dixie Deb' shown above.  Upright standards and almost drooping falls.  I have no idea what the bug might be.  Maybe a Texas mosquito?

Blue, or Violet?  Great signals.  Still the open form.  Note the bud next to it.

 The next two pictures are not Louisiana irises.  To learn more about various iris species, visit this website.

OK, iris experts.  No, this is not a Louisiana iris.  It is a hybridized iris.pseudacorus.  I'm pretty sure this is 'Roy Davidson' or something like that.  Notice that it has the open form, or is it the pendant form?

A nice example of iris.virginica blue.  It certainly has the open form, but is not a Louisiana iris, so who knows what the Species Iris Group of North America (SIGNA) people call this form.

To learn more about Louisiana irises, visit their web site at Louisiana Irises.

To learn more about different species of irises and the crossing of difference species of irises, visit this website - SIGNA.

To Learn more about irises, visit the American Iris Society.

Next time we will look at the many colors of Louisiana irises.

Understanding Louisiana Iris, Part 1: I. giganticaerulea

By Joe Musacchia

                        

The Louisiana Iris is one of the most misunderstood yet versatile irises. It’s been called a water iris, which is not technically correct. Some will grow in water, some will not. If the foliage is totally submerged, they will most likely die. Most will grow well in bog conditions, but some will not. They have been grown from Canada to Mexico and in many countries abroad. They grow from the marshes and swamps of Louisiana to the deserts of Arizona.  The secret to their successful cultivation is understanding the cultural differences of the five species that make up this diverse group of iris, and being able to recognize these traits. The species that make up Louisiana iris are I giganticaerulea, I fulva, I brevicaulis, I nelsonii, and I hexagona. Most of the new cultivars on the market today have all 5 species genes in them.  My purpose here is to help you to look at a cultivar and recognize these traits, so that you will have some idea how this cultivar will perform in your garden and what culture requirements are best.

I. giganticaerulea

Iris giganticaerulea (or giant blue) is the tallest of the Louisiana Irises. It can grow over 6 feet tall in the right conditions. It was discovered and named by Dr.John K. Small in 1925 while he traveled by train through South Louisiana.

Iris giganticaerulea growing on a bayou side

                     

In its native area I. giganticaerulea grows all winter. Hot, dry summers may bring on dormancy, with the plant all but disappearing until late August when the weather cools, and rains return. It is most commonly found in marshes, along bayou banks, in ditches, and the edges of swamps. It can be seen growing in as much as 2 feet of water. Even so, if the plant goes dormant during the summer, an early return of standing water can spell their demise if the growing tip is submerged for an extended time.

White  I. giganticaerulea
(  Barbara Elaine Taylor )

I. giganticaerulea blooms very early in the spring with rapid bloom stalk development. The flowers are very large, generally 4-6 inches across. The color is a blue-purple with an underlying white. A white form, lacking the blue pigment, has been collected in the wild and brought into cultivation. They require a lot of sun during their growing season (winter in Louisiana), but will tolerate some light or afternoon shade in the peak of summer in that region. They possess tall, straight stalks with little or no branching. Their rhizomes tend to be large, and will often grow a foot or more in a growing season, causing the plant to travel.                                                                                                                                                         

One year winter growth

I. giganticaerulea’s core traits have an implication on their performance in various geographic locations. Because they bloom early, hybrids that have strong giganticaerulea traits may not perform as well in areas outside their normal range. Most commonly, unless the rhizomes are directly exposed to extreme temperatures (as in the case of frost heave), the plant will survive and grow, but might never produce bloom. In New York State for example, where spring freezes are common, the tender, early bloom stalk will succumb to the assault. You will get a lot of lush green foliage all summer, but no flowers. Between the early bloom season, the tendency for the rhizomes to travel in beds, not to mention the need for division every two or three years, some find them a difficult plant to employ in a home landscape. These same traits make them ideal for landscaping around ponds, rain gardens and areas where too much water is a problem. Recognizing these traits in modern hybrids can help you select the best Louisiana cultivar for success.  

        Damaged rhizomes showing increase 

Benny Trahan shows off an  almost 7ft I. giganticaerulea

        

                                                                                                                                                                                                                         

Coming Up:  The Traits of  I. Fulva