The rhizomes in these pictures have been dug up to replant. Please note the ends of the rhizomes have been cut back to a solid texture. This removes any rot that is present. If there are new increases as shown in these photos, try to save as much of the rhizome as possible. You must however cut the rhizome back to a solid end. Many people soak the newly dug rhizomes before replanting in a bleach water solution. The mix is 1 part bleach to 10 parts water. You may soak the plants for 30 Minutes. Also the tops are cut back to about 6 inches of leaves remaining. If the roots are long, it is okay to cut those back to 4 inches or so long.
This group of photos shows a growing clump of irises that has developed rot in the center or mother rhizome. The rot is scraped or cut out until solid rhizome remains. After the rot is removed, Comet cleanser is applied by shaking a generous amount to the infected area. If soil has been scrapped back to clean the rot out, it would be okay to leave the soil off for a few days before covering the rhizome again. If the rhizome was already exposed when you started, do not cover it, just leave it exposed.
This group of photos two different clumps that were dug up for replanting. Please note in the finished rhizome pictures, the tops and roots have been cut back and the old rhizomes that do not have green tops have been removed. The old rhizomes with no growth are no good and should be thrown away. Replanting these old rhizomes could promote rot in your beds.