w/o info on ambient weather.. its hard to come to any conclusions ...

excessive early heat.. followed by cold ... can cause bizarre growth patterns.. which can include leaf variation .. i see it in hosta all the time ... its called the drawstring effect.. where the center tissue is actually growing faster than the edge ... perhaps causing the pattern you are seeing .. i have no clue if it carries over to iris ..

throw in a lot of rain perhaps [???] ... just another variable ...

can you give us any info regarding how spring developed this year ...

otherwise .. but for the fact that the pic was taken in noon sun.. causing it to be a bit washed out.. they dont look chlorotic to me ... in fact they may look a bit sunburned .... is there any chance they flushed in a long term cloudy/rainy weather cycle.. then were hit with a few days of blistering heat???? [we had a cold may with 6 inches of rain.. feeling like the sun would never shine again ... where everything leafed out, fat and happy .. followed by 3 days near 100 ... i have a lot of what i call sunburn ...]

it is obvious that it is a rather large happy clump.. which leads me to think there cant really be any significant soil issues ... things just dont grow that aggressively when they arent happy ...IMHO ...

ken

Here is a link that might be useful: link on drawstring

Sometimes that happens to mine when an inside leaf cannot break through and gets jammed up inside older leaves. I don't know why they get jammed up- maybe a short cool spell makes the outside ones stop opening and the inside ones, being more protected, keep growing.
Just a guess.
Renee

Thanks to you both for your thoughts. I would say that the weather that you describe, Ken, is pretty much the kind of spring weather we get a lot of here in South Dakota. Kind of hard on plants, I guess. We also had the cool weather and the six inches of rain, and are sending record amounts of water down the Missouri as we speak, and will keep doing it until July they say. We also had the couple of surprise sunny days, not 100 degrees, but in the nineties. I haven't really seen this clump of iris in the flesh, but might go to see it and it's overgrown, untended, bunch of garden friends on Friday with my friend who sent me the picture. I did go out and look closely at my iris, and I think I have a couple of wavy leaves on Burst of Glory. I looked more closely at it since Bambi or some vandal kid ripped off its tallest stalk and threw it down on the ground. It really looks bit up, so I think it was the ungulate rats we have around here. Bummer. I saved one bloom and it's perfuming my dining room in a vase.

I've had Sheer Bliss have it's bloom stalks get jammed up like you describe, hosenemesis. (what a great name!) but I haven't really noticed it happening to leaves. I would think if there was a weather related problem that my iris could have, I would have it. I think I asked about this on bloom stalks a couple of years ago on this forum, and was told it was due to it getting really cold when the bloom stalks were forming. This happened one year when it went down to 12 degrees in April. All my iris had short, twisted bloomstalks. A very different look for iris.

Thanks again!
Barb