|Semi-double. American Peony Society Gold Medal Selection with rose shaped flowers, a yellow center and cream colored carpels. These old fashioned classics are loved for their hardiness and unbelievable bloom. Double and semi-double are rounded flowers in which all or most of the stamens are developed into petals, giving them their exuberant beauty. They rarely need dividing but if you want to spread the wealth, divide in the fall and make sure to plant the eyes not more than 2" below the surface. Care tips: Deadhead after flowers fade.