It wasn't 12" across only 10"
Although they are called tree peonies, shrub peonies would be more apt. (perhaps if they live to 100 years they might make trees?)
Yesterday I was asked if they were perfumed, well the pale pink ones are, the darker ones not. They come in yellows as well but I don't have those in my garden so I don't know.
It's no wonder these fabulous plants were reserved for the Japanese Emperors.