Hi there, hoping someone here can tell me what's going on with my irises...

In two clumps, the scapes are coming up with buds. But on some, about halfway or three-quarters up the scape, the thing will look like it has been severely pinched and twisted, and the scape falls over, buds never bloom, scape turns brown and the leaves start to turn, too.

What's going on? We haven't had a frost, no one in my immediate area seems to know what weed-killer is, so I know that's not it. Other irises in clumps nearby (in the same bed) are just fine... It's just these two. Can they be saved? I'm hesitant to throw them out because they've been such beautiful bloomers in the past.

Anyone have any ideas? Thanks