Just got a peony from my wife for fathers day and am curious how large it will get and how much sun it needs. It's currently about 15" tall.
Sarah is a gorgeous peony-nice gift! She'll get pretty big. Mine gets a good three feet tall, and at least that wide. (Well, it did before I divided it to share, it'll need a couple of years to get back up to snuff) The flower heads are HUGE, so you may want to give it some support. Shouldn't be an issue this year, but something to keep in mine for the future. Mine is in an eastern exposure, and so is out of most of the wind, and stands pretty well on it's own. Peonies like full sun, although in your zone I'd guess it could take some afternoon shade. They're really pretty easy to grow. The smell of this one is wonderful..almost smells like roses, to me.