I am seeing a lot of this now when I am snapping off bloom stalks. Maybe I am planting them wrong, but so many of them seem to want to grow down into the ground and then rot when the ground gets wet. Is it maybe slugs? Do some irises tend to grow more upright than others? I am into the "HATE" part of my iris LOVE/HATE relationship now. We have had a lot of rain lately too, which seems to make it worse - beats them down into the ground. I suppose some of the clumps need to be raised, which I have done without moving them. Stick a spade under one side, push up, add dirt under raised part, etc all around clump. Thanks, I think I just answered my own question!

If the fans/leaves are going upward and then curving downward to the soil I'd suggest trimming the leaves back a few inches. Many do that anyway a month or so after bloom time; I don't normally except when there is a lot of leaf spot or in some circumstance as you are experiencing.

Thanks, Dave. I hadn't thought that it might be the weight of the long leaves. That might work in some circumstances.