I was under the impression that the first year bloom of a newly planted iris was formed in the previous location of origin so whatever happened there is an unknown in most cases. The general rule I think is that about 50% will bloom the first year but that is from the place of origin. Many of mine bloom the first year but not the subsequent year. It is hard to figure out what triggers increase and bloom volume other than the care you give, the unpredictable nature of the weather and the individuality of the cultivar. I think.......
