The Hong Kong orchid tree (Bauhinia blakeana) is grown both for shade and for its attractive red-purple blooms. The large flowers appear during the summer, fall and early winter each year and it grows in U.S. Department of Agriculture plant hardiness zones 9b through 11.

The Hong Kong orchid tree can grow as tall as 40 feet with a canopy 25 feet wide. Like many trees, the Hong Kong orchid tree grows best when it gets some routine pruning.

After Planting: Prune off dead or diseased branches that appear after planting, but don't prune off any healthy, growing branches. The Hong Kong orchid tree should be left alone for the first year after planting, as pruning healthy branches will stress the tree. The tree will spend a great deal of energy establishing its root system for the first year.

Initial Pruning: Beginning in the second year, the Hong Kong orchid tree should be pruned in late winter, after the tree has finished flowering for the season. Prune off any weak and spindly branches, any branches that cross over and rub against other branches, and any low-lying branches. Cut these branches back to the main branch or trunk. Cut the branch straight across and cleanly, without breaking or tearing the branch. Breaks and tears can lead to decay and infection, which can result in disease spreading from the tear to the rest of the tree.

Pruning for Shape: Hong Kong orchid trees may have one or several main trunks. The top of the trunk is called the “leader” and will direct the growth of the tree upwards.

Be careful not to prune back the leader, as this will inhibit vertical growth. Rather, prune back the side branches of the tree to create a rounded shape. Hong Kong orchid trees will need this routine pruning for the first three to four years. After this, the tree will only need pruning when it’s necessary to maintain the shape.

Lower Branches: If you would like a higher canopy, the lower branches of the tree can be pruned back to the trunk as the tree reaches maturity. Cut these branches off in winter.