Description

The Hong Kong orchid tree is fast-growing to 25 feet tall and 30 feet wide. It is hardy in U.S. Department of Agriculture plant hardiness zones 9b through 12b. Both its parent species are hardy to USDA zones 9 through 11. Young trees can be slow-growing to begin with, and early growth can be open and awkward-looking. Prune the trees in summer to encourage closer branching and development of the typical umbrella-shaped canopy. Trees prefer moist, well-drained soil and tend to have short trunks.

Branching

Trees develop an umbrella-shaped canopy but pruning is needed to shape the crown. The branches of young trees are long and arching and often irregularly placed. Trim the long branches back during early growth, aiming to encourage branches to grow at a 45-degree angle from the trunk and to point away from the crown's center so sunlight can penetrate to deeper areas. Remove any crossing branches. In older trees, the branches droop toward the ground, and need pruning to allow space for pedestrians and vehicular traffic if necessary. Trees can have multiple trunks, but you can prune them back to a single trunk, if desired. The branches have brittle wood, so prune the tree to allow good air flow and to lessen wind resistance. The trunk and branches have gray bark.

Flowers

Showy rose-purple to orchid pink flowers are 5 to 6 inches wide and fragrant, resembling some orchids in shape. They occur in clusters of about 20 buds at the ends of branches from late October through March, with the longest bloom period of any of the orchid trees. Fallen flowers can carpet the area beneath the tree. The flowers are sterile and can't form seed pods or set seeds, eliminating the litter of seed pods produced in other orchid trees. Hong Kong orchid trees are propagated by grafting or by air-layering or rooting cuttings.

Leaves

The blue-green leaves are up to 8 inches wide with a distinctive bilobed shape. A deep notch at the tip of the leaf gives the leaf an outline resembling the footprint of a camel. The tree tends to be evergreen, but partial leaf loss results from dry weather or cold temperatures. Sometimes trees completely defoliate if drought occurs after the flowering season. A well-pruned tree provides dense shade. Prune the tree after flowering, especially if some leaf drop has occurred, so the branching is more visible.