another image. It is so weird.

several itoh varities have this features but not known with bartzella. wow that's amazing!!!

Congratulations! It maybe a bud mutation, similar to the bi-color Chinese tree peony "Er Qiao". Maybe If you don't cut it, it may reappear some day.

See the following pic, looks a bit like yours:

Here is a link that might be useful:

Peonea05: Can you tell me what other Itoh cultivar may also have this feature? I would love to get something like that.

littlebin: Thank you for the comment. What do you mean don't cut it? Should I just leave that stem as it is and not cut it next spring? How about I let it go to seed and see what would seed do? Let me know, since I really want to preserve this feature.

I actually have Er Qiao not far from this Bartzella. This year I got five buds, but none opened, which I suspect is caused by the spring freeze damage. Hopefully next year I will be able to have more flowers.

Here is another picture of the pink Bartzella

Singing in the Rain, Magical Mystery Tour, Julia Rose etc. The flower of these varieties usually changes to three different colors as the flower ages. For example for Julia Rose, the flower start from red to orange then to yellow.

Hi, Shoto, I don't know exactly how you can preserve this feature. Probably the best way is to do grafting. Not cutting and keeping that particular stem probably can help. Letting it go to seed probably may not help since most Itoh peony are infertile.

Wow, how interesting. Such a beautiful bloom too; I love the flares. It will be interesting to see how this plant performs in the future.

Shoto, if you are interested in acquiring another Itoh that shares this feature, I would definitely look into Lemon Dream. This photo instantly reminded me of it. It can have yellow and lilac blooms on the same plant, and some flowers can have sections that are lilac and sections that are yellow as well.

I have the same thing. It first appeared last year and I was advised to cut the stem at the bottom where it starts...which I did.

But it is back this year. So just going to leave it.

It is a mutation of the original root. If you just leave it you may loose it or that section of the plant could smother the rest.

If you like the flower label that stem then this fall dig down, locate the root, then remove.

My Krinkled White peony has two deep pink blooms this year as well as the white. I have had the plant for several years and this is the first time this has happened.