Jack, there are a zillion plicatas, but it looks a bit like Stepping Out, which was a very popular one. I would suggest purchasing a rhizome of Stepping Out and growing it near to this one for comparison.
-"If I can’t drain a swamp, I’ll go pull some weeds." - Charles Williams
It could also be several others. Does your camera reflect it's true color? Purples are often hard for cameras to photograph correctly. I ask this only because there are possible matches dependent on the correct shade of purple (yes there are really that many similar purple and white plicatas out there).
"The chimera is a one time happenstance event where the plant has a senior moment and forgets what it is doing." - Paul Black
Sure looks a LOT like 'Stepping Out' to me. That was what I thought of immediately. Blue beard tip checks out, too. Not saying definitively that this is your iris, OP, but it sure is a ringer for it.
