Hi Heidi again
I forget to mention – your asking for what type – species is the tree peony group P.suffruticosa !!
P. suffruticosa – Is not a species – it is a group of different tree peonies
So in fact.. it is a hybrid tree epony – where different types of tree peonies ocur if you breed them further.
I learned this by ; Will mc Lewin ( UK )
He has written a book, about this and specialy the tree peonies.. we call P.rockii – as in chinese is Ganzu Mudan – Peony Rockii and Ganzu Mudan is the title of the book