Have you had any freezes?
kay

Need water? Too hot?

No late freezes, fair amount of rain, and actually a little on the chilly side.
Whatever it is/was seems to have stopped.

Did they actually wilt, or did the stalks come up curvy? I had bloom stalks this year that came out s shaped, but they bloomed ok. I've had them mishapen before, but never to the extent of this year. I attributed it to cool temps, but I really don't know. It hit the earliest blooming TB iris, later ones were fine.

any history of the lawn company spraying your lawn???

ken

Thanks for all the suggestions. No lawn service for me or my neighbors. Out of 30 some varieties I grow, this is affecting 5 of them. I wish I had a camera to post a picture of this.
The stalks seem to be fine, then develop a soft section and bend over like a candy cane. Then after a day or two, that droopy part either breaks off or creases and bends down. If I cut off the affected part, the rest of the stalk blooms fine.
I am having quite a problem with the leaf spot this spring, and I think that may be affecting the stalks as well.

I've never seen that before. Hopefully, everything will right itself next year.

when i first read this post i had never heard of what you're talking about, and now i've lost 5 stalks in the high winds of the yesterday because the stalks were starting to wilt like yours had, and not so much wilt as just droop a little and the stalks become sort of soft but only in one section. all of the one affected are first time bloomers for me, so it might just be this years growing conditions coupled with the first time blooming of the plant.

are yours new or have they bloomed before?

They have all bloomed before, although the ones affected by this wilting are doing poorly overall this year. Lots of fungal leaf spot due to the rainy cool weather we've been having.