Tree peony (Paeonia suffruticosa Andr.) is native to China and is a magnificent, beautiful and attractive ornamental plant. Flowering is critical in the development and life-cycle of most plants. The time of flowering largely determines the socio-economic and cultural values of plants. In China and Japan, tree peony cultivation is a traditional practice in the flower industry. Hence, regulating the time of flowering of tree peony is critical for potted and cut flower supply to these markets during the New Year and the Spring Festival periods. This book represents a research into the floral physiology, growth and development of the plant, since this could enhance the quality and rate of flower production.