Despite the crazy weather, all my tree peonies did well. I was shocked! Hana Kisoi did this strange thing, and I wanted to know if others have had this experience. The tree is about ten years old, and has borne beautiful light cherry /pink flowers every year. This year I had the usual 10-12 flowers, but just as they were going by, 4 new buds began to open. They were beautiful, healthy, same size, but they were much darker than the first group, a lovely very deep cherry, clearly the same flower but a much darker version. Is this common? I've never seen it. By the way. I'm in zone 5.
I don't have Hana Kisoi, but my pink TPs change their intensity of color from year to year, sometimes on different parts of the plant. I think the American Peony society has references for Japanese TPs. The books weren't in my library holdings when I last looked. I assume these darker buds weren't from the root part of the graft.
I wonder if you have a sport. David Austin created a dark pink named Mary Rose that spontaneously produced white flowers and light pink flowers, each of which he cultivated and marketed separately. It is not uncommon for the white version to start producing dark pink flowers, just like the original plant. Do you think that this could be occurring?