Immortality is a reliable rebloomer for me. Most of the time I do not have to stake. This year my Iris were taller and I think that had to do with how much rain and what time of year during the plant growth cycle it came. Does yours rebloom for you? If not it may not be immortality. Mine is not as tall as many of my tall bearded. Do reconsider. A patch of white Sparkles at night. Plant other white flowers in the same area. You might grow to love that wild zone.