Unlike the common orchid tree (Bauhinia variegata), this tree’s flowers are sterile and do not produce seed pods that might aggravate allergies or cause litter, nor does it produce any fruits, making it a good choice for public gardens and urban landscaping. It does, however, produce a moderate amount of litter from fallen flowers and leaves later in the season. Its bright colors and flowers attract hummingbirds and other pollinators.
Light
The Hong Kong orchid tree tolerates a range of light conditions. It will bloom in full sun, partial sun or partial shade.
Soil
This tree is best grown in loamy, sandy soil that is slightly acidic. The soil should be moist and well-drained. If planting in clay soils, be sure to add amendments such as compost to create a more crumbly texture.
Water
Although the Hong Kong orchid tree prefers a moist loamy soil environment, its water needs are low to average. It is very drought tolerant, and overwatering may cause it to bloom less vigorously.
Temperature and Humidity
This tree is best suited to a tropical or subtropical climate, but will tolerate a light frost and can withstand temperatures down to 22 degrees for short periods in winter. It likes to dry out between waterings so a humid environment is not ideal for this tree.
Fertilizer
The Hong Kong orchid tree benefits from a fertilizer application three times a year, in spring summer and autumn. Use a basic granular organic fertilizer, mixing it in with the top layer of soil, and be sure to check the weather forecast to make sure it’s not going to rain for at least 3 days after you apply it. This will ensure the fertilizer starts to feed the tree and enrich the soil and is not washed away too quickly by rain.
Pruning
It’s very important to prune Hong Kong orchid trees while they are young, as they may grow somewhat irregularly. Regular pruning will give them a solid structure and create a uniform shape to the crown of the tree. The tree’s upper branches tend to droop a bit as it grows, and will need to be pruned to keep walkways clear.
Propagating Hong Kong Orchid Tree
Since this tree is a fruitless sterile hybrid, it doesn’t produce trees from seeds. But you can grow it from cuttings taken in summer and rooted over bottom heat: a method used to induce root growth by keeping the branch end coolant dormant. Branches can also be induced to grow roots by what is called layering: either by burying a section in the ground, or scarring a small section of the branch with a knife and then wrapping it with damp sphagnum moss and enclosing in a plastic bag. Roots should being to form within 10-14 days.
Common Pests and Plant Diseases
Though generally a very hardy tree, the Hong Kong orchid tree is somewhat vulnerable to pests and diseases. The main pest problems are caterpillars who munch on the leaves, mites who might cause the flowers to wilt, and borers who feed on the soft wood of the trunk and branches. They are also somewhat susceptible to leaf spot and leaf scorch. There may be a tendency for the tree to have nutritional deficiencies such as potassium, which can be fixed with regular use of the appropriate fertilizer.
How to Get Hong Kong Orchid Tree to Bloom
One trick to help promote vigorous blooms on this tree is to avoid overwatering. Letting the soil around the base of the tree dry out between waterings helps to promote more vibrant growth and more flowers.
Common Problems with Hong Kong Orchid Tree
Because it is so fast growing, the wood of this tree is not very dense or strong, making it susceptible to wind damage or breakage in storms. Planting it in a protected location near a building or similar structure can help prevent weather and wind damage.
