The fall before our daughter Martin-Lane was born, nearly 13 years ago, we planted a tree peony. The first flower bloomed on April 16, the day she was born, and on her birthday for the first 9 years of her life. A couple years ago a cool early spring delayed the flowers opening until the end of April. This year they bloomed on April 5th.
Tree peonies have larger and more delicate flowers than more common bush peonies. The trees grow slowly and prefer not to be moved. Tree peonies buds are formed above the ground on the woody stems during the fall so take care not to prune in the fall or you will not have any flowers the following spring. With bush peonies next years buds are also formed in the fall but in the underground rhizome so cutting leaves will not affect the next springs flowers. Tree peony flowers only last a few days on the tree or in a vase. Like all peonies if you want to use the bloom as a cut flower cut as soon as the bud feels like a marshmallow, before the flower actually opens. Place the cut stem immediately in cold water, most likely the flower will open in a few hours.