Perennial peonies called herbaceous peonies fade back to the ground every year. The plant stems push up in the spring while the roots remain dormant beneath the dirt. Woody, deciduous shrub peonies are called tree peony. They shed their foliage in the fall, but unlike herbaceous peony, their woody branches do not die back to the ground. Itoh peonies are a hybrid cross between herbaceous and tree peonies; while they do die down to the ground in the fall like herbaceous peonies, they exhibit tree peony-like growth and flowering traits.
Before they became beloved ornamentals, tree peony, which are native to China, were prized as a therapeutic plant. A tree peony can reach a height and width of up to five feet (1.5 meters) in around ten years and is a larger, woodier relative of the ordinary herbaceous peony. They are widely coveted for their huge, prodigious blooms, which can reach a diameter of up to 10 inches (25+ cm).
These blooms occur in single or double shapes and bloom from late spring to early summer. They are great cut flowers. Tree peony do not produce the sweet honeydew sap that herbaceous peonies do, which is what draws ants to their flower buds.