This is a general guide to culture to assist those unfamiliar with growing Louisiana irises. It contains some general suggestions that may be useful in adapting Louisiana irises successfully to your growing conditions. This should be kept in mind when planting them.
Remember to cut off unwanted seed pods after bloom to prevent unwanted rogue seedlings from comming up in your beds!
LOCATION OF BEDS
Irises can be grown in regular perennial beds providing additional water is supplied during the growing season, in boggy areas, in and around ponds or waterways in up to 15" of water and in pots in water gardens. Louisiana irises are quite at home in a wide variety of soil types from almost pure clay to sandy loam. Sandy soils will benefit from the addition of organic matter to help hold the moisture. Clay soils can be made more friable with the addition of organic matter. Louisiana irises love sunlight. They should have at least a half day of sun. It is only with ample sunlight (4-6 hours or more) that the irises will bloom. Insufficient sunlight will cause scanty bloom as the rhizomes will not be able to store ample resources for proper growth to support bloom.. In areas having very hot dry summers shade in the afternoon may prove beneficial in reducing the loss of water from the plants. Iris beds should not be located where the plants are in competition with plants with extensive root systems as these deplete both nutrients and water. If for landscape purposes it is desirable to plant them in such locations, a modified container type garden can be constructed to prevent the invasion of the roots of these plants. The soil can be removed from the desired planting area and then lined with plastic and the soil replaced. It must be remembered that under these conditions the water and fertilizer must be more carefully monitored.
PREPARATION OF BEDS
Beds for planting Louisiana iris should be prepared well in advance of planting. Soil should be acid a pH of 6.5 or lower is ideal. Irises are heavy feeders. Ample quantities of organic matter (peat, composted leaves or manure,or sphagnum along with a balanced fertilizer 8-8-8 at the rate of 8-10 lbs. per 100 sq. feet of bed should be worked into beds six weeks in advance of planting.
Spacing of iris
Iris of the same variety should be placed about 10-12 inches apart to allow for increase. Keeping about 24-36 inches between different cultivars allows for increase and keeps the varieties separated.
Louisiana irises should be transplanted or divided about
every 3 years to insure bloom. In their natural habitats, nutrients
are brought in yearly by the flooding from waterways. You will
know if the flowering decreases that it is time to separate and
rework the beds.