I saw a bloom of 'William A. Setchell' once that measured 10" top to bottom and nearly 6" across. It was huge. The tall stalks were stout, but still had to be staked. I've never grown it myself, but it's known for having one of the largest bearded iris blooms. It has the old form of its age. Introduced in 1938, I think other purple iris of around the same vintage have been distributed under the name, but if the bloom is really large its probably correct.
