The tallest iris I have is 'Material Girl', registered at 48 inches. I don't think it has ever gotten quite that tall for me - there is something about my growing conditions that leads to iris growing shorter than their genetic potential. Anyway, it is still pretty tall, is the last iris in my garden to bloom, and has thick substance with the deep markings on the falls that you can see in the photograph. Its stems are strong - I never have to stake it.

It's very tall here too.

I had the tallest bearded iris, 55 inches tall. Only it wasn't a variety, but my seedling Giorgio X Mysterioso . I had to throw it away, as it fell when several flowers opened at the same time, despite the fact that its stems were quite strong and could withstand the first upper opened flower even with a slight wind.

(late reply here)
Melanie, in my garden, hits 47 "

https://garden.org/lists/item/...

I did have flop issues one year. But by and large, i don't.