Looks like a Paeonia tenuifolia (fernleaf peony). They're gorgeous and that looks to be a very nice specimen.

Thats a fernleaf? looks somewhat different from the pics I've seen. This one looks almost like it has bamboo leaves. What a beauty! Love it.

It is a fernleaf and I went to great lengths to protect it when I put the patio in, replaced my roof etc. because I thought it was pretty unique and it is gorgeous in bloom as well as beautiful foliage for the rest of the summer.

Here is a tighter shot:

I posted the last image before I added that it does look kind of like Paeonia tenuifolia but I thought the same thing that you did musaboru, the leaves are different. They are more fernlike than any of the other peonies I have added to my yard but not as fine or narrow as the fernleaf pictures I am looking through to try to identify it.

Diana,

It is definitely not a p. tenuifolia. The foliage on p. tenuifolia is much much finer and the plant would be shorter as well. The plant in your picture looks taller. It looks like a hybrid of some type, but I'm not sure. Also I was wondering if it might be Peony 'Okinawa' because this one is supposed to have narrow leaflets. Here are some links to p. tenuifolia and 'Okinawa'.

p. tenuifolia
Okinawa

Not disagreeing that it mightn't be a hybrid, but there does occur variation within the species. 'tenuifolia' translates to 'slender leaved', which is often rendered as 'fern leafed'.

Attached is a link to a picture w/2 P. tenuifolias in it. If you look at the leaves of the 2 plants in this picture, the forward plant has rather broader leaves than the plant to the rear. Commonly, P. tenuifolia's leaves may be as slender as a dissected leaved maple, but again, there is variety in the species.

Here is a link that might be useful: link to some pics

The species tenuifolias have leaves of all different widths between hair like to very course. Since they interbreed you can easily have two plants of the same family with different foliage. Look at Carsten Burkhart's site under Te to see pictures of different types.

Here is a link that might be useful: peonies