Things that can affect the bloom time of transplanted irises are:
Time of the year transplanted.
How long they were out of the ground before being re-planted.
Length of your growing season.
Fertility levels of your garden.
Amount of water.
In my zone only about half of the newly planted irises bloom the next year. Sometimes they do bloom that first year, but have a sub standard stalk and blooms. Other ones will bloom that first summer after planting, then skip a year and bloom later. Some just put out a lot of increases and don't have enough energy to bloom. But what ever happens, if they live, they will bloom eventually.
Some varieties are kind of pouty after they are transplanted and take a while to establish. Beverly Sills, and All About Spring are two that are like that for me. They just don't like to be moved. Immortality on the other hand likes to be moved, and if left in one spot too long they tend to bloom less frequently. This is my experience anyway, can't say that it's research based.
