World of Irises: Growing Louisiana Irises

by Ron Killingsworth

Louisiana irises growing in Mooringsport, LA

Far too often I hear various Master Gardeners, and other flower lovers, say they just simply cannot grow Louisiana irises. I even gave a talk, several years ago, on growing Louisiana irises to a group in Fort Worth, TX, who told me they cannot grow Louisiana irises. That’s funny, because they grow lots of them in Dallas.

Louisiana irises growing where they were simply dropped on the ground

My personal experience is that if you throw a Louisiana iris rhizome down on the ground, and it can reach dirt, it will grow right there. Not long ago I removed all the irises from a raised bed to amend the soil and just piled the rhizomes on the ground next to the bed. After amending the soil (with compost) I replanted the rhizomes. Obviously I missed a few and left them on the ground outside the bed. Later that fall, I took this picture of the irises growing right there where I had placed them in the grass next to the bed. They were growing as well as those I had carefully planted back into the raised bed!

'Fringed Gold' growing next to a pond

While it is true that Louisiana irises like to have a lot of water, fertilizer and sunlight, they will grow reasonably well with less water and at least 50% sunlight. In really hot climates, I find that they do much better if they have afternoon shade in the heat of late afternoon. The real beauty of Louisiana irises is that it is almost impossible to overfeed or over water them. Yet they grow quite well with other plants. If you do not give them enough water, food and sunlight, they will produce less bloom and less increase. If you are not growing them for sale, but simply growing them for their beauty, then who cares if they have less than "garden judging" performance?

Massive planting of Louisiana irises

The above picture was taken in front of my house. This area was once my vegetable garden and we planted about 6000 Louisiana irises there, temporarily, about eight years ago. They were dug from Marie Caillet's famous pond in Little Elm, TX, and were mostly unidentified hybrid and registered Louisiana irises. We were able to identify some of them and move them into beds; however, most of them remain as "surprise" irises who have lost their identify. This soil was just common gardening soil, un-amended, and they receive very little care and are not often fertilized, yet they put on quite a show every year. I hesitate to guess how many irises are in this huge planting. It gives me quite a view from my front porch during bloom season.

Louisiana irises growing with poppies and other "wild flowers"

This picture shows Louisiana irises growing with poppies and "hardy glads". And, admittedly, with a few weeds. But, although they receive little maintenance and very little fertilizer, they continue to do quite well.

Louisiana irises growing with Tall Bearded irises

We have a lot of trouble growing Tall Bearded irises in Louisiana because of the heavy spring rains and very hot summer temperatures. Some of the old species TB's do quite well, while more modern hybrid TB's last about two years before they burn up in the hot sun or develop rhizome rot from too much water.

Louisiana irises and iris.virginica growing around a pond with Caddo Lake in the background

If you have a water feature, a pond, or a tank (Texas talk) you can grow Louisiana irises in the edge of the pond or around the pond. A small pump installed in the pond can provide the water to keep them very happy. Not all Louisianas do well growing directly in the water.

Louisiana irises growing with other plants

These Louisiana irises are growing with bushes and other flowering plants. They receive very little sunlight other than direct noon sun and are seldom fertilized. Yet they continue to produce at least two or three blooms per bloom stalk and to increase enough each year to bloom the next year. This is not the ideal way to grow Louisiana irises commercially and for sale, but if you are growing them to simply enjoy them, then this method works well.

Louisiana irises growing with wild flowers

This is an area of the property we call the "deer meadow" and we plant wild flowers there each year. The Louisianas in the background are in dug beds, lined with plastic, and are watered through an irrigation system that pumps water out of Caddo Lake.

Louisiana irises growing in pots

Many people chose to grow their Louisiana irises in pots. This makes it a lot easier to keep the different cultivars separated. Louisianas are know to "creep" and when planted in beds, will soon creep into the space of their neighbor unless you dig them and divide them every two to three years. Pots also make it easier to control weeds. These pots have holes in the bottoms but you can use pots without holes to help conserve water. If you use pots without holes, I suggest you punch some drainage holes about three inches below the soil level to keep the water from standing above the soil.

Louisiana irises growing with Tall Bearded irises and other flowering plants

You certainly would not want to grow Louisiana irises in your cactus beds but they will grow with just about any other plant. If you do not feed them and water them enough, they simply will not produce the "garden judging" required number of bud positions and bud count, nor the required increase each year.

Louisiana irises growing in dug beds, lined with heavy plastic

We grow irises commercially and using a backhoe dig beds about two to three feet deep and four feet wide by as long as the space allows. We line the beds with plastic and fill the beds with amended soil. Again they are watered from a pump in Caddo Lake. This method works well in our area.

Raised beds are easy to make with landscape timbers. Just line the bed with plastic and fill with good compost.

These Louisiana irises are happy with about 50% sunshine and grow well in this raised bed. Of course, when you make it ideal for irises you also make it ideal for weeds!

Rhizome ready to plant

A rhizome ready to plant should have the foliage trimmed back and, if necessary, reduce the size of the rhizome. Plant the rhizome about 1 1/2 to 2 inches below the top of the soil. Keep it moist, not drowned, until the new growth starts to appear.

To learn more about the Society for Louisiana irises, click here.

To learn more about growing Louisiana irises, click here.

OK, class is out for the day. Now let's just look at some of my favorite Louisiana irises.