I was checking the 4-rhizome clump in my pic above and pulled off an old leaf. The leaf was mushy at the bottom so I tugged on another. The 'new' part of the rhizome moved a little too much so I dug the entire clump. That rhizome definitely had some rot so it was trashed. The 3 other rhizomes were cleaned and bleached and look pretty good. The iris is one of the common dark blues and not worth a lot of effort but the 3 good ones will probably be replanted.
There had never been an iris in that location until this one was planted last summer. It was in 90% full sun with good ventilation. The only thing I can come up with as a cause of the rot would be too much watering. The bed is raised about 12 inches and filled with a very well draining soil mix.
