I obtained mine from a property we bought down the road. The family had run a nursery from this property and had several clumps planted in the yard. I'm afraid I don't know the name of it. I do have a pink one but will not divide that one. I moved it about four years ago and it is still recovering. I came across it by accident, it was being sold by a nursery and they must have had it mislabeled. It is a beauty!
The photo below is before I moved it, now it is only 1/4 the size :(