I had a thought today. Some time ago there was a thread somewhere in regards to how large a piece of rhisome was needed to make a "start". has anyone ever tried the rooting hormone( like you woulduse on "cuttings") on iris? I wonder if thats what the Dutch use with their process? I have started/incresed rhisomes with pieces 1/2"-3/4" long,and had 3/4, or so of them "take". How about it? Anyone ever try it?. ..Arlyn
There was a man on iris talk several years ago worried that his Dusky Challenger was not increasing well and he feared loosing it so he took a rhizome from another iris that was not as important to him and made 1/4 - 1/2" slices and placed them in seed starting soil. Many of the slices he made developed fans. I do not think he used rooting hormone with them and I do not know if he used a rhizome that had bloomed or not.
I have read where cutting the tuber roots of certain fern leaf peonies into small sections then planting them can produce adventitious roots and buds. There is no logical reason for the technique to fail to work with irises. One time I had an iris which was to be disposed of but was too close to another to dig. I chopped it into small pieces by using a sharp shovel and next year I had new small irises all over the place.