With its dramatic foliage and long-blooming colorful flowers, the Hong Kong orchid tree (Bauhinia × blakeana) makes a very striking specimen planting in warm, arid climates. Though it is not a true orchid, the shape and rich colors of the flowers are reminiscent of orchids. The tree was first discovered by French missionaries on the western coast of Hong Kong and is the official tree of the island. These beautiful tropical trees are often referred to as evergreens, but in truth they’re deciduous and drop their leaves in late winter before forming spring buds. They have large butterfly-shaped leaves, and produce large, delicate-looking but sturdy blooms in shades of purple and rose pink, sometimes with some white variegation. At 6 inches across, the blooms are twice the size of other orchid tree flowers. The flowers of the Hong Kong orchid tree last from November through the end of March, at a time when there aren’t many trees flowering in the winter landscape.
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.
|Botanical Name||Bauhinia blakeana|
|Common Name||Hong Kong orchid tree|
|Plant Type||Tropical evergreen|
|Mature Size||Up to 40 ft. tall|
|Sun Exposure||Full sun to light shade|
|Soil Type||Moist, well-drained loam|
|Soil pH||Acidic to neutral|
|Bloom Time||November through March|
|Flower Color||Reddish, purple, pink|
|Hardiness Zones||9b-10 (USDA)|
|Native Area||India, China, Africa|
Hong Kong Orchid Tree Care
This is a rapidly growing tree that can reach up to 40 feet in height, and its wide canopy (which creates ample shade) needs space to spread. Rather than one central trunk it usually forms several main trunks. Be sure to plant at least ten feet away from your house or other structure to avoid problems later on. These colorful trees make a beautiful statement planted in rows about 8 to 10 feet apart, as a property border or accent for a larger garden design.
The Hong Kong orchid tree tolerates a range of light conditions. It will bloom in full sun, partial sun or partial shade.
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.
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.
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.
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.
How fast do Hong Kong orchid trees grow?
These are very fast growing trees that can grow up to 24 inches in height in a year. It’s crucial to prune them in the first few years to ensure strong structure as they grow.
Can you grow Hong Kong orchid trees in containers?
You may grow them in containers for the first year or so, but due to their rapid rate of growth it’s best to plant them in the ground while they’re young and less than five feet tall.
Are Hong Kong orchid trees toxic?
This tree’s parts are not toxic to dogs, cats or humans, but as with any garden plant not specifically grown as a food crop, it should not be eaten.