I don't have a single peony, tree or otherwise, that I've had for that long! I think I'd email Cricket Hill, Solaris or one of the other growers who sell tree peonies for advice. I know my oldest one had died all the way back to the ground before and came back without apparent damage so I don't think it'd hurt the plant but I'd want expert advice on which to remove and how far so that you'd end up with the best looking plant possible.

Your peony are so beautiful. it take them long time to reach that tall. please do not tim them shorter. I wish I have them on my yard

Thank you for all your reply. I decided not to trim or cut back at this point.

Here are some of my flower pictures .

Wow, beautiful! Your yellow one is so lovely!

When I was a member of MAPS, I attended a session about pruning tree peonies. I remembered the recommendation was to prune off very old non productive tree peony branches all the way to the base in order to rejuvenate new growths and allow newer branches to develop and grow better. Also, if you see branches that grow into each other, you should prune those off also. Though the tree peony in question at the time was 15 years old. So maybe you can mark those old non blooming branches (or ones that produce small flowers) next year when it is blooming so that you can have some idea which ones to prune in the fall.

Beautiful. they decorate your house with their beautiful breath taking color.

they also give you the picture perfect to veiw from the inside thru the window .

. I have 18 of them but they are all small.

Beautiful! I would cut back just the tallest branches and see what happens.