Agreed. It's definitely NOT P. Carol Kanzer. The foliage alone is enough to discern that, as CK would have much narrower, grassier leaves and would likely be noticeably smaller growing.
As for actual ID, your guess is as good as mine. Unless you know the provenance of the plant, and lacking a label, it's one of those that I'm sure could be any number of crosses involving schlimii and relatives crossed with longifolium or similar.