I have never had split stems either. I have had stems go soft and bend though due to lots of rain. Not this year yet except on a stem of Quaker Lady.
As always I am behind in posting. Some of the blooms are still in bloom three weeks on so I hate to post and miss the best shot. I know that sounds crazy but I like to have all of my pictures of a variety before I choose pictures.
Spoon's Velvet Elvis:
Innerst's IB Grindelwald always shows up for some blooms.
Iris tectorum (aka Japanese Roof Iris, crested iris)
Tectorum like shade. I am adding this picture so you see how very different the color looks when sunlight hits them.