That's a beautiful Tree Peony. Not seen a double yellow like this one.

Yes, in short, they respond very well to pruning. Cut out the longest stems. Reducing their length is fine also as this will encourage lower shoots to become active and start growing.

We pruned one of our tree peonies severely last autumn - it has responded by putting on a lot of new lower growth and looks far better and less leggy.

Thank You Both, for the good advice :o))))