Purple orchid tree (Bauhinia variegata) has an unusually long bloom season for a tree, with blossoms that make their appearance in late winter before the tree leafs out and last until early summer. The fragrant flowers bloom in bright pink, purple and white, and resemble showy orchids. It is an ideal size for small residential landscapes, growing 20 to 35 feet tall with a similar spread. Orchid trees are hardy in U.S. Department of Agriculture plant hardiness zones 9 though 11.