I believe this is a Princess Chiffon. It is getting too large for the location....I have it tied up so that it doesn't hang over the sidewalk. I usually prune in late fall to the first good bud and take out dead stalks. Can this plant be pruned further back in order to reduce it's size?

I'm not a tree peony expert so I'm not going to even try to give a good answer, just had to say that is a beautiful tree peony and welcome to the forum!

I can't imagine why you can't cut down a few stems after the plant blooms. The one negative is that cutting down some stems to the base may end up forcing more new growth so you may end up back to square one.

Is there multiple branches at the soil line? How about dividing it in the fall to make two or three new smaller plants, some of which you can then give away, sell or trade? Cricket Hill has good info on dividing.

https://crickethillgarden.word...

Someone else correct me if I'm wrong please.

Gorgeous plant, it's on my wish list but I have not found a supplier in Canada.

Tree peonies can take severe pruning. You can cut the plant all the way to the ground it you want to, it will come back, no problem. I don't know how much that will control the size though. You have a very well established tree peony. It looks very happy. And is gorgeous.

You could graft the heck out of it this fall and end up with more plants too. (We have a grafting tutorial on this forum.)
I haven't ever actually split a tree peony. So I can't speak to that. I have moved one once,with little disturbance of soil and it barely made it....but it did. So that is a possibility for fall as well,

Welcome.