I only know them from climates with cold winter and to not be evergreen. Some plants are evergreen when winters are not so cold, but i couldn't say about these.

I know of no peonies that are evergreen, tree or otherwise, regardless of climate. They are fully herbaceous perennials or deciduous shrubs.

I have 1 tree peony, and it is not evergreen, which suites me fine because I like the look of its new leaves in spring; shades of green edged in maroon.

My knowledge is limited to a tree peony called Paeonia lutea var. ludlowii. It's NOT evergreen. All the leaves fell off and the whole plant took up a lot of space and fanned out like a brolley without its fabric. So horrid and taking up so much space that I removed it. Boy, how I have missed the flowers - one of the best yellow blooms I have ever seen. I have another one bordering between a purple or pink, most of the leaves have fallen off. This time round, I won't get rid of any of them.

I have two more herbaceous peonies which die down completely as if they didn't exist and would come back every year without fail.