Louisiana Or Hexagona Irises

Irises have been cultivated for several centuries for the elegant form of their blooms. While this plant has been grown for several thousand years in Egypt and the areas around the Mediterranean, available records show that irises have been grown in England for several hundred years. In ancient times, people have formalized the beauty of various iris varieties like the flag iris, I. pseudacorus, and I. germanica, a forerunner of the present day bearded irises, in their art works. In addition, there are several texts that detail the utility of these plants for therapeutic purposes. However, a group of irises found in the southern regions of the United States aroused very little interest among botanists till about a hundred years back. The native Indians, nevertheless, have admired the exquisiteness of the flowers of these irises for centuries.

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Commonly called Louisiana irises, these plants are in bloom during spring. In the northern hemisphere, they flower during April-May, while the flowering season of these plants in the southern hemisphere is October-November.

Today, we find different types of irises each with distinct features and beautiful in their own right. However, all these iris varieties have actually been bred from five original species as well as their natural hybrids. Nearly all of these original iris species and their natural crosses have their origin in the Mississippi Basin. However, only one of them, known as the I. Hexagona, is indigenous to Alabama, Florida and Georgia. This particular iris variety has derived its name from the six noticeable ribs found on the seed cage. The plant was first described as I. hexagona way back in 1788. A few years later, botanists described the two more species called I. brevicaulis and I. fulva. The other two irises in the group were described only as late as the 20th century. While I. giganticaerulea was described in 1929, I. nelsonii was described much later in 1966, following its discovery in the latter part of the 1930s.

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There was a time, precisely speaking the early part of the 1900s when these irises were found growing profusely in marshes and bayous close to the place which is currently known as downtown New Orleans.

While Hexagona irises only comprise five species, each of these species has an assortment of characteristics that offer vast possibilities for breeding new cultivars having widely contrasting traits or according to the requirements of the hybridizers. In fact, the natural hybrids came into existence before these plants were discovered by botanists and by then, had introduced a wide array of color variations that is found in any other iris, except for the bearded irises.

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Now the pertinent question is what helps a novice grower to identify a Louisiana iris. In fact, it is not easy to always recognize Louisiana iris, as the appearance of their blooms differs widely. Their form varies from willowy to floppy, from being dishevelled to frilly, while the flowers of some of the Louisiana irises have an appearance that is not very different from the contemporary Siberian cultivars. Usually, the standards and the falls of these flowers partly cover each other in such a manner that when one views them from above, the flowers seem to be made up of two curved triangles that are placed on top of another. Just close your eyes and visualize a rounded Star of David version! While the hues of Louisiana irises differ greatly, so far it has not been possible to attain a true fire-engine red bloom in any type of iris. However, the flushed coloring of the iris variety called I. fulva produces cultivars having more specific red compared to that found in other iris series.


The iris variety known as Louisiana iris basically requires three things - sufficient water supply, an acidic soil (any soil that is appropriate for growing azaleas and camellias will be suitable for Louisiana irises too), and a very rich soil. Different from the climatic conditions, a grower is able to control these three aspects to a great extent. Therefore, it is not surprising that currently people are growing Louisiana irises in places having very different climatic conditions. However, the growing season as well as the flowering time also differ depending on the climatic conditions in different places.

The Louisiana irises often start flowering at the onset of spring (mid-March to late March) and grow for approximately eight months every year. If these plants are provided with sufficient water, they grow almost throughout the year in Los Angeles where the summers are more arid compared to that in Louisiana. However, the usual flowering season of Louisiana irises begins in mid-spring (middle April to late April).

It is surprising to note that Louisiana irises are also found growing naturally in the cold Midwest United States, where the climatic conditions are hardly and different from what prevails in their natural habitation. In the cold Midwest, Louisiana irises continue to exist even through the frozen winters, provided they are protected with heavy mulching. It appears that these irises are somehow insulated due to snowfalls or even the absence of snow. In this place, Louisiana iris plants generally grow for roughly five months and have a long flowering season during summer. The flowering usually begins in June second week and continues through July. In general, it has been found that the smaller the stature of an iris is, the more cold-resistant it is likely to be.

While Louisiana irises have a preference for warmth and like to relax in full sunlight, they also possess the ability to do with half-day's sunlight or filtered sunlight throughout the day. This is an excellent instance of the adaptability of these plants.

However, the plants need some protection from heat when grown in areas where summers are too hot. If the summers in your area are very hot, you may protect the plants by providing them with mulching. At the same time, you need to ensure that the moisture is conserved, and weed growth restricted.

Louisiana irises have a preference for very fertile, heavy soil and they will thrive well in standard beds, in a bog, along the side of water bodies, and also in standing water, provided the depth of water does not exceed 1 inch (2.5 cm). These iris plants also grow well in pots kept in ponds.

Louisiana irises are perfect iris varieties to be grown in containers and placed on the patio, provided they are supplied with sufficient water on a regular basis. These plants have rapid growth during spring. Therefore, it is advisable that you place the containers in a plate that is filled with water frequently during spring as well as the flowering season of the plants. In addition, Louisiana irises are known to be heavy feeders. Therefore, you also need to provide them with good quality fertilizers when grown in containers. Properly decomposed animal manures are excellent for this purpose. When the flowering season is over, you should remove the plate/ saucer. This is actually imitating the natural habitation of the plants where the swamps become dry during the summers.

At the same time, you need to bear in mind that iris foliage provides nourishment to the plants. In fact, nearly all Louisiana irises will have better growth after their dormant phase during summer, provided they are provided with sufficient water during the hot and arid spells. The foliage will die during the latter part of summer and fall, but you need to abstain yourself from pulling the dead foliage, because this may damage the growth of the rhizome. Eventually, the dead leaves will dry up and mix with the mulch naturally.

Planting and division

By nature, Louisiana irises are extremely adaptable and keeping this aspect in mind, you can move these plants through the year. However, usually Louisiana irises should be planted as well as divided immediately after their flowering season or during the fall. Undertake dividing, first by excavating the rhizomes and trimming the foliage down to roughly 8 inches (20 cm). Plant the divided rhizomes to a depth of approximately 1 inch (2.5 cm). When you are planting or replanting Louisiana irises it would be good if you give them sufficient time to develop new roots, prior to watering them profusely. Following this method it will help to put off the hazards of the rhizomes developing rot, especially if the soil is damp and before their roots are capable of taking up moisture from the soil. This also applies to the irises that are grown in pots and is also true for those that are meant for growing in water. The later variety of irises requires no less than four weeks to develop new roots and they ought to be submerged only after the new roots have emerged.

Louisiana irises have a propensity to multiply rapidly, especially when they are grown in water. They should ideally be divided once in three years soon after the flowering season or when the plants begin to produce lesser number of blooms due to congestion of the clumps.

Apart from the blooms of Louisiana irises, which are strikingly beautiful, even their seed pods may be large and contribute to the attractiveness of your garden. The seed pods of this iris variety usually droop from their stalks resembling something like large green eggs. Owing to their great size, the seed pods of Louisiana irises are heavy too. People who wish to save the seeds for propagating the plants will require staking the plants as soon as the seed pods emerge. The seeds of Louisiana irises have a corky coating enabling them to float. This is one of the reasons why the seeds of this iris variety are dispersed far and wide in their marshy native land.

Germination becomes more difficult when the corky covering of the Louisiana seeds dries out. Therefore, when grown in mild climatic conditions, the seeds of Louisiana irises need to be sown soon after they mature. However, in cold climatic conditions, the seeds should not be sown till the onset of spring. Ideally, you should plant these seeds in pots using a fertile and porous planting mix. This planting mix can be prepared by properly blending equal parts of adequately rotten manure and sand. Cover the seeds with roughly 1/2 inch (1 cm) of this planting mix and ensure that the bed is always kept moist as well as in shade.

Before trying to plant the seedlings outdoors, you should wait for the seeds to develop a robust root ball. The seedlings may grow up to a height of 6 inches to 8 inches (15 cm to 20 cm) and be nearly root-bound before you make any attempt to  transplant them to the permanent positions outdoors. The plants are likely to bloom in the second season of their existence.


Usually, the flowering stems of Louisiana irises ought to be erect or elegantly curved. However, there are some exceptions, especially in the instance of a number of iris varieties that have been derived from the species I. brevicaulis. These cultivars generally have zigzag traits, which are common to I. brevicaulis. In addition, the height of the flowering stalks of Louisiana irises also should be balanced with their blooms. In ideal situations, the flower buds of this iris variety should be arranged in a manner that the foliage does not interfere with them. Moreover, each flower stalk of Louisiana iris should bear no less than six buds. In terms of the form of the flower, all forms that are characteristic of this iris variety are acceptable. The color of the flowers should ideally be unsullied as well as clear. The flowers of Louisiana irises and their various cultivars are found in all the primary colors and their different combinations. In fact, the blooms of Louisiana irises may come in vivid, pleasant, blended hues. They may also be found in bicolors that may comprise harmonizing, but contrasting colors. In addition, the blooms may also exhibit new color patterns, counting prominent veining, halos or even spray patterns.

The flowers of Louisiana irises are of various different forms, including open, flat, pendent, overlapping, flaring, double, partially or semi-double or cartwheel type. The falls and standards may possibly be ruffled. On the other hand, the style arms of the blooms, which are vital for the attractiveness of Louisiana irises, may come in colors that contrast with the hues of the falls and the standards. Alternatively, the style arms may even be edged or ruffled having diverse colors. The signals of the flowers, which are basically markings that help the pollinating bees and insects to land at the appropriate spots on the flowers, may emerge in the same location where the beards occur in the bearded irises. Usually, the signals have a yellow or orange hue and may differ greatly - sometimes being very large and on other instances being almost absent. In fact, flowers of a number of Louisiana iris cultivars have signals on the falls as well as standards. A number of flowers may also have crests or line signals that are usually little elevated and pubescent. In fact, Louisiana irises differ so much in size, foliage, flower form and color that one has to learn plenty of things to be able to decide which the ideal varieties for their garden are.

Louisiana irises are excellent for growing in a water garden or bog garden. At the same time, this variety of irises is also a good choice for growing in herbaceous borders and beds. Moreover, they are also excellent for using as cut flowers and it is also very easy to arrange them. Even after you cut the flower stalks of these plants, the buds keep on opening and the flower remains in bloom for many days. Usually, the flower stalks of Louisiana irises grow up to a height of anything between foot and 5 feet.

Although Louisiana irises are not as popular as the tall bearded irises and are also not grown as extensively as the latter in all gardens, their flowers come in various colors, forms as well as sizes. These attributes of Louisiana irises make them a wonderful choice for growing in perennial gardens. The flowering season of Louisiana irises come when the bearded irises have stopped blooming for the season. In fact, the flowering season of this iris variety usually lasts for about six weeks, sometimes even up to two months. This attribute is not seen in several perennial iris varieties.


I. hexagona
This iris species has its origin in the south-eastern regions of the United States, close to the Gulf of Mexico and the Atlantic coast. Hence, I. hexagona has a preference for warm summers and moderate winters. The flowers of this iris species have an elegant blue hue, at times tending to be lavender with slender yellow-hued signal on their falls, while the standards are erect and slender. The stems are branching and they differ in their height, ranging from 12 inches to 36 inches (30 cm to 90 cm). Like the stems of the other Louisiana irises, the foliage of I. hexagona is yellowish-green and lance-like.
I. brevicaulis
Like I. hexagona, this iris species also produces blue flowers, but the color of the blooms is lighter compared to the former species. On the other hand, I. brevicaulis has an open form. This species is actually a dwarf among the species belonging to the Louisiana irises and is native to places that are more north to places where I. hexagona is found growing naturally. I. brevicaulis is often found growing in open meadows having high moisture content during the growing season of the plants. Compared to its cousin, the stalks of this iris species are smaller usually growing up to a height of anything between 10 inches and 14 inches (25 cm to 35 cm). The flowers appear at a low height and always below the foliage. I. brevicaulis is somewhat resilient and when grown in its native Louisiana, the plants bloom between early to the middle of May - much later compared to other iris varieties. The stalk of this iris species has a remarkable feature - it is meandering at the nodes.
I. giganticaerulea
This iris species also bears blue-hued flowers. However, the shades of the blooms may be quite different - having a touch of wisteria as well as lavender to white. The stalks of I. giganticaerulea are erect and tall, at times even growing up to a height of 66 inches (165 cm). The flowers are slender and appear above the foliage, contributing to their elegance. This is truer when the plants grow in clumps. I.giganticaerulea plants have a preference for fertile soil and it can even thrive in inundated conditions. They have the aptitude to grow in total sunlight and also limited shade in open marshes.
I. fulva
This a robustly growing iris plant which often reaches a height of up to anything between 18 inches and 32 inches (45 cm to 80 cm). I. fulva is distinguished for bearing pale red, orange-red, copper-hued and sometimes, though seldom, yellow blooms, which appear on stems that are just about straight. The falls as well as the standards of this iris species are drooping, while the style-arms of the flowers are small and partially erect, making them resemble a butterfly seated on top of the flowers. When this iris was discovered for the first time in 1814, it actually created a sensation in Britain owing to its remarkable hue. In Louisiana, this iris species grows in abundance. It has also been found growing in the wild as far towards the north as Ohio. This iris species is usually found growing in open marshy lands, forested swamps where there is abundant sunlight and also beside the canals and streams. I. fulva can thrive in full sunlight as well as partial shade. This is among those irises, which can be grown without much effort. Usually, I. fulva blooms early in summer.
I. nelsonii
This iris species was discovered as recently as 1938 and it is found growing in the wild in a very small region of Abbeville, Louisiana. I. nelsonii is a tall growing species and the branching stalks of the plant may often grow up to a height of 44 inches (110 cm). The flowers of I. nelsonii have elongated reflexed falls as well as standards, which make the blooms appear somewhat languid. The color of the blooms of this iris species varies from red to pale terracotta and may come with a tinge of lavender. The flowers of I. nelsonii are quite similar to the blooms of I. fulva and like the latter species, these flowers also have made it possible for the breeders to bring in the red color in their hybridizing programs. This is the main reason why breeders consider I. nelsonii to be a significant member of the Louisiana iris family. I. nelsonii has been responsible for giving rise to numerous amazingly beautiful iris cultivars that we see today.
Aril and Arilbred Irises
Bearded Irises / Culture / Species
Bulbous Irises
Evansia or Crested Irises
Japanese Irises
Median Irises
Miniature Dwarf Bearded Irises
Novelty Bearded Irises
Pacific Coast or California Irises
Reticulata or Dwarf Bulbous Irises
Scorpio or Juno Irises
Siberian Irises
Spuria Irises
Tripetala Irises


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