|'Cardinal Vaughan' bears semi-double, ruby-purple flowers. The tree peony, or Mouton peony, is a deciduous shrub that bears large, showy, cup or bowl-shaped flowers from late spring to early summer. Leaves are dark green with blue-green undersides and are deeply lobed. Originating in China, the tree peony is long lived and may reach a height and width of 7 feet. Soil should be deep, rich and well-prepared. Remember to plant the grafted union of the tree about 5 or 6 inches below the suface of the soil. Peonies thrive on sun (part sun in warmer climates) and plenty of water. Plant where they will be protected from wind. The best time to prune is in late winter or early spring while the plant is still dormant.