Every iris is an individual and has their own habits. Immortality is one that seems to like to be moved, and when left untouched, it doesn't bloom as much. (at least for me) Edith Wolford is a picky princess, and she blooms when she wants to.
. . . and that's not very often for me. Some take a year or so to settle in, and then bloom well, others bloom every other year in my zone. These are usually slower to produce increases. Of course here the growing season isn't as long as some people have. But mostly baring a lot of rot, Hale storms, or iris borers,
the majority of them do quite well, and bloom most years.