"Bearded Iris Growing Cycles" Part 2

(this info is from "Magic of Irises" by Barbara Perry Lawton, p.174)

The block of time between the period of spring growth and the late-summer period of root growth is optimum for dividing and transplanting bearded irises. During this time, you can work at a leisurely pace on digging the irises, trimming the rhizomes and replanting them, because it will be good for the rhizomes to dry out for a few days. It is best to spread the rhizomes out on newspapers in a dry, shady spot for several days so they can dry out. Any soft or cut places will develop a corky surface as they dry---this is called callusing.
As an illustration of the tough extremes to which you can put large bearded rhizomes, I have left bearded iris rhizome clumps out of the ground lying in the sun for a week or more and they seemed to be better off for it. This is an excellent way to get rid of fungal diseases, especially any root rots which may have crept into the bed. Smaller rhizomes will dry and callus more quickly than large ones. Shorten the drying period for smaller rhizomes.
When digging the iris clumps, make sure you keep them separated correctly according to species or cultivar. Some find it easierr to keep the clumps of each variety of bearded iris on separate newspapers together with their labels from the garden bed. Separate the rhizomes and examine them carefully. You may have to cut or break the rhizomes apart. Use a sharp knife to remove diseased parts. Clean the knife after each cut to avoid spreading disease. An easy way to do this is to wipe the blade, then put it back into household chlorine solution for a few seconds.
To make it easier to handle and replant them, cut the foliage fans back to a length of 6 to 8 inches from the rhizome. Trim back the smaller bearded irises proportionately. At this point, write the species or variety on the remaining leaves with an indelible marker so that identification will not be a problem while you are making new garden labels. Trim up the separate divisions, making sure that each fan of leaves has a short piece of rhizome with healthy, strong feeder roots. Some growers like to make divisions that are Y-shaped so that there are 2 fans per division, each on a smaller arm of the Y, and sharing the leg of the Y.
When you replant the divisions, make sure that the growing ends of the rhizomes don't face each other. Face them outward so that the plants don't become crowded as fast. When your divisions have been made, trimmed and marked, be sure to let them dry and callus in the sun for a few days. If you do that, you don't need to dip them in fungicide or any other drying or rooting substance."
(to be continued...)