This is taken from the linked site. Hope it helps you.

SEED REPRODUCTION

Seed pods will develop on most wild irises. If pollinated, each pod will produce from several to about 60 cork-like seeds. This method of increase is very important to iris hybridizers in developing new forms and colors but is slow. All the seeds in a pod may not germinate the first year.

Gardeners who desire large quantities of plants for mass plantings may be interested in using seeds also, if trueness to variety is not important. Most Louisiana irises are hybrids and their seedlings will vary in color, size and form.

If iris seeds are left on the stalk to mature fully and harden, they germinate very slowly. The fully matured, late harvested, dried-out seeds will go into what is known as a "rest period" and it may take several years for all of them to spout. However, you can hasten germination of iris seed by harvesting them when the seed pod is still partially green. Planting at harvest time (June and July in Louisiana) will produce a higher percentage of seedlings by fall and early spring.

Here is a link that might be useful: http://www.louisianairis.com/louisiana.native.iris.htm

Thank you very much for the information Iris Gal.