Louisiana Iris Planting Instructions & Care Guide(Growing Condition, Varieties, Colors, etc)

Louisiana Irises are among the most popular bog plants. Their foliage is lovely and may be used as a background or to supplement the other plants in the bog. Their blossoms are obviously appealing, since they are among the most exotic flowers in the world. The plants may be cultivated in any damp place and are ideal as transitional plants between the pond and the landscape since they can be planted along the pond’s edge or immediately in the water itself.


The phrase “Louisiana Iris” refers to any of a vast group of beardless Irises that are either one of five wild species, natural hybrids of those wild species, or hybrids created via the laborious efforts of enthusiasts all over the globe. These people’s efforts have resulted in forms that vary significantly in size, colour, shape, and bloom duration. Experiments have been conducted in Louisiana Irises to induce “polyploidism,” or the multiplication of chromosomes, using colchicine and other agents. Many of the most spectacular types have resulted from these studies, with advances in bloom size, petal material, and bud count per inflorescence.

Louisiana Irises are classified as members of the family Iridaceae, genus Iris, subgenus Iris, section Spathula, subsection Apogon (beardless), and series Hexagonae. The Irises’ taxonomy is still being worked out, but this is where we are right now. Apogon, or beardless, Irises include the Laevigatae (Japanese and other moisture-loving Irises), Sibiricae (Siberian Irises), Spuriae (Spurias), Californicae (Pacific Coast Irises), and several other less well-known Irises.

The native species’ usual range ranges from the Gulf States up the eastern shoreline through the Carolinas and west to the Mississippi River Valley. The blending of five major species is taking place. They are I. fulva, from which all red varieties are derived; I. giganticaerulea, from which the larger blue and white hybrids and varieties are derived; I. brevicaulis, from which the purples and smaller blues are derived; I. hexagona, from which many lovely purple hybrids are derived; and I. nelsonii, a natural hybrid of I. fulva and I brevicaulis that has This species provides us with a lot of yellows.

For decades, these species and their numerous naturally occurring variants have been happily mixing it up in an area known as the “Golden Rectangle” of Irises, providing enthusiasts with a rich legacy to draw upon. The “Golden Rectangle” is a tiny region that stretches roughly 100 miles inland from the Mississippi River delta west to the Texas-Louisiana state boundary in southern Louisiana. The convergence of the ranges of the five main species was produced by climatic and topographical conditions in this location. One of these species, I. nelsonii, is the result of a cross that happened in a remote place long enough ago for the result to be recognised as a distinct species. The region surrounding New Orleans was a vision of magnificent beauty every spring at the time of its “discovery” by enthusiasts, with millions of Iris blossoms dotting all of the wetlands and lake edges in the vicinity. Early collectors were very lucky to have witnessed such a thing (see John Muir’s account of the wildflowers of California’s central valley) and to have such a resource to draw upon.

Unfortunately, human habitat devastation has resulted in the extinction of most of these natural populations, leaving us with collections of enthusiasts to draw upon. And what a collection they’ve amassed! For many years, the yearly gatherings of the local Iris organisations featured collection expeditions all throughout the region. From the 1920s to the 1940s, hundreds of variations were collected, but only a small percentage of the gathered types proved to be valuable as hybridising stock. White, lavender, blue, yellow, red, purple, bicolors, ruffled petals, smooth-edged petals, doubles, rebloomers, tiny and big blooms, and tall or short plants are among the current types.


Louisiana Irises are rhizomatous plants, which means they have a specialised, thickened stemlike structure that creeps over the substrate, generating new leaves from the leading end (apical bud) and branching to variable degrees behind the apical bud. Pickerel plants (Pontederia), Thalia, Marselea, and several Sagittaria species are also rhizomatous plants in the aquatic plant world. Some types’ rhizomes branch excessively, ultimately forming colonies of plants in which the rhizomes are crossed two or three deep. Others branch more cautiously, resulting in more open colonies with less tangled development.

All of the varieties and species in this category can withstand a broad range of growth circumstances, from complete submergence of the rhizome beneath several inches of water for months at a time to surviving high above the water level in locations that sometimes dry up. Of course, they prefer settings in which there is always sufficient of water, but once established, they will withstand some shortage of water. Because of our moderate winters and lengthy growth season, Southern California has been considered as a heaven for Louisiana Irises.

They will also survive a wide range of soil types. They appreciate a rich, sandy soil with lots of mulch in regions where they will be grown away from the water. Plants in this soil type will reach full height and blossom freely if kept wet and given enough light. They like sandy, loamy soil with less organic matter when grown in shallow water than when cultivated on the land. Frequently, naturally existing pond debris accumulating around the colony’s roots as it develops works best. However, when beginning from scratch, I like to mix soil, making sure to include enough of composted pond muck and timed-release fertiliser (Osmocote 14-14-14). I also mix in a tiny amount of bone meal to the soil to promote stronger roots (more divisions) and bigger blossoms.

In southern California, fresh leaves emerge in November, with significant growth commencing in December or January. New development continues throughout the winter, with new rhizome branches gaining a lot of size in preparation for the spring bloom. This procedure is postponed until the spring thaw in colder climes. Plants will begin to grow inflorescences in February or March, depending on the weather, the circumstances, and the genetics of the plants. In general, the sooner the commencement of blossoming, the warmer the condition. Some kinds, like “Clyde Redmond,” can rebloom in the autumn, but for the most part, what you see in the spring is what you get all year. As previously stated, genetics also influences bloom time. Because some of the original species bloom at somewhat different times, we have “early” and “late” flowering cultivars. Each inflorescence lasts a few weeks, and the whole blooming season, including early and late bloomers, concludes by the first week of June. I’ve never had one in bloom for the Del Mar Fair, which starts on June 15, although I’ve been close on a number of times.

If you wish to create seeds, you should remove the old inflorescences after the blooms have finished. The plants will keep producing new foliage until late summer, when the older leaves begin to fade. This will continue until the new fans arrive in November/December.


Louisana Irises are quite simple to maintain. They are very disease-resistant and sensitive to just a few pests if grown in the correct location.

The most important factor is adequate air circulation. There are many causes for this. One is that Louisiana Irises are subject to a rust-like fungal infection, which will ultimately kill the plant on its own or force the plant owner to discard the plant in disgust. Rust is caused when spores come into contact with a leaf. This might be performed by the wind, ant feet, or infected blades or hands. The easiest strategy to minimise disease contamination is to keep the plant bed from getting overcrowded and to avoid regions with poor air circulation. Spraying with a light oil and a suitable fungicide on a regular basis is also a good idea. In addition, I always strive to remove the dead leaves. However, sometimes aesthetics dictate that the leaves be removed before they are entirely dead. I’m hesitant to do this since pulling or cutting them off before they’re entirely dead produces holes that seem like open invitations to infection to me. Spraying freshly cleaned plants with oil/Funginex solution (see below) is an excellent idea.

Another reason to keep the air moving is because white flies and/or scale insects may attack Irises. Ants carry them in, and if circumstances are favourable, they will flourish, creating all of the usual issues connected with these insects. The majority of these issues may be solved by following generally recognised gardening procedures.

Rust is the most difficult issue to solve, thus it should be anticipated and addressed as soon as it is identified. I’ve had some luck with a combination of paraffin oil (also known as “Ultra Fine Oil” or “Sun Oil”) and Funginex. If the illness has been detected, this must be administered every couple of weeks throughout the growth season, and less often if it has not. The issue seems to be more common when the humidity is high.

I’ve discovered that trays put at an adequate depth are the ideal container for growing Louisiana Irises in water. The explanation for this is straightforward. Because Louisiana Irises are rhizomatous, they need some movement room, which a tray offers. Two things will happen if they are placed in a tall pot. One, the plant will rapidly approach the pot’s edge and attempt to grow through or over it. If it manages to climb over the edge of the pot, it quickly attempts to descend to follow the substrate. If it cannot find a substrate, it will decay away. If it doesn’t come out, it stacks up against the edge of the pot and rots in a tangle beneath the mud. Furthermore, since a deep pot is so deep, the plant will never utilise all of the soil, but with a tray, the roots finally fill the tray, leaving no wasted muck in the pond. Furthermore, the shallowness of the tray enables the soil to breathe more freely, lowering the chance of anaerobic bacteria forming. A kitten litter tray is enough in most instances, although bigger trays are also suitable. It is important to avoid purchasing anything that is too huge and difficult to transfer effortlessly.

Irises should be given lots of rich soil to flourish in when planted in the ground. Adding bone meal to the soil can speed up rootstock division and result in bigger and more frequent flowers in the spring.

As with other Irises, the clumps should be split apart and given new soil every couple of years, particularly if they are in containers. If you want a nice bloom the next spring, try this in southern California throughout the autumn and winter months.


Louisiana Irises are really simple to cultivate and will offer you years of pleasure if you give them what they require. They like shallow water or damp soil, as well as sandy, acidic soil with little nitrogen. They flourish in either full sun or light shade. They bloom earlier in the year in sunny settings than they do in shady ones. They may never blossom at all in deep shade.

Irises will always be a favourite in water gardens. People will constantly return for more of their bright and unusual flowers. With continuous hybridization and testing with colchicines, a Crocus bulb extract that modifies plant genes, and other therapies, the future seems promising.

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