Louisiana irises can be propagated by dividing the rhizomes or by planting seeds

Rhizome division

Identify healthy rhizomes: Look for firm, plump rhizomes with healthy roots. 

Divide the rhizomes: In the fall, dig up the irises and break off the new plants from the old rhizomes. 

Replant the divisions: Place the divisions in a bed or container, making sure the top of the rhizome is about half an inch below the soil.

Water and mulch: Water the bed thoroughly and add a 2-inch layer of mulch. 

Seed propagation 

Harvest the seeds: When the pods are yellow and cracked, harvest the seeds.

Plant the seeds: Lightly score the pod and remove the seeds. Plant the seeds in a pot with potting soil, and cover with about ¾ inch of soil.

Water and place in a shady location: Keep the soil moist but not soggy.

Monitor the seeds: Push down any seeds that pop up to the surface.

Transplant the seedlings: In late January or early February, transplant the seedlings into a garden bed.

    Additional tips

    Divide irises during their dormant season in early spring or late fall. 

    Improve the soil with organic matter and fertilizer.  Louisiana irises prefer acidic soil with a pH of 6.5 or lower. 

    Dividing irises encourages new growth and increases their bloom capacity.