|H. serrata and its cultivars are also sometimes listed as H. macrophylla subsp. serrata. 'Bluebird' is also sometimes listed as 'Acuminata'.
H. serrata is loosely related to the Bigleaf Hydrangeas, but has a more delicate appearance, with slender stems, narrow leaves and smaller flowers. It is native to mountain woodlands of Japan and Korea and is hardier in constitution than H.macrophylla. Grows to 3 to 5 feet in height, with flower color ranging from blue to pink to crimson.