Hydrangea macrophylla is popular for its full flower shape and colorful flowers. It is not only a common potted ornamental flowering shrub, but it also can tolerate semishady environments and is an important part of the understory in many areas, with high ornamental and ecological values. The cymes of H. macrophylla include decorative floret and nondecorative floret. The decorative nature of decorative florets is mainly due to the large and showy sepals that help attract the attention of pollinators. Nondecorative florets, on the other hand, have small and inconspicuous sepals and are mainly responsible for seed production. Since decorative florets greatly enhance the ornamental value of H. macrophylla and are more popular and preferred by consumers, they have become a major breeding target.