Bauhinia × blakeana
Common Name: Hong Kong orchid tree 
Type: Broadleaf evergreen
Family: Fabaceae
Native Range: China
Zone: 9 to 11
Height: 12.00 to 20.00 feet
Spread: 20.00 to 25.00 feet
Bloom Time: November to April
Bloom Description: Rose-purple to rose-crimson
Sun: Full sun to part shade
Water: Medium
Maintenance: Medium
Suggested Use: Flowering Tree
Flower: Showy
Leaf: Evergreen
Other: Winter Interest

Culture

Winter hardy to USDA Zones 9b-11. Best in full sun. Tolerates light shade. Best with moderate but consistent moisture. Grows well in a variety of soils as long as well-drained. Thrives in heat but leaves may brown along the edges in dry heat or droughty conditions. Established trees have respectable drought tolerance, however. Best sited in locations protected from cold winds and frost. Foliage will suffer damage when temperatures dip below freezing and tree will usually not survive winter temperatures that dip below 26 degrees F. This is a sterile hybrid (flat seed pods seen on other species are absent) that must be propagated by vegetative cuttings, air layering or grafting onto seedlings of one of the parent species. All trees in existence are descendants of the hybrids first cultivated at the Hong Kong Botanical Gardens, all of which were propagated from the single accidental hybrid first discovered in 1880.

Noteworthy Characteristics

Bauhinia x blakeana, commonly known as Hong Kong Orchid Tree, is a small often multi-trunked evergreen to semi-evergreen flowering tree with an umbrella-like shape featuring an irregular rounded crown. It typically grows to 20’ tall, but occasionally in optimum conditions to as much as 40’ tall. This hybrid has no native territory as such because it is only known today from trees propagated from a single accidental hybrid discovered in the wild and collected in 1880 near the ruins of a house along the shore of Hong Kong Island near Pok Fu Lam. Cuttings were taken by a nearby French mission, with subsequent cuttings taken from the mission trees for inclusion at the Hong Kong Botanical Gardens. This hybrid is not only considered to have the best ornamental flowers in the genus but is also considered to be one of the most attractive flowering trees in the world. Its parents are believed to be B. purpurea x B. variegata. This hybrid was first botanically described in 1908. It was chosen as the floral emblem of Hong Kong in 1965. Its flower image in white became the center of the red Hong Kong flag in 1997. In the U.S., this tree is frequently cultivated in Hawaii. It grows well in warm parts of California, Arizona, southern Florida and Texas.

Fragrant rich rose purple to rose crimson 5-6” wide orchid-like flowers with paler veins bloom over a long late fall to spring (November to April) period. Each flower has a 5-petaled corolla with the uppermost petal being darker toward the base. Flowers are shaped like some orchids (to 6” wide). Flowers of this hybrid are larger than the flowers on species plants. Bi-lobed, light to medium green leaves have yellowish green veins (6-8”). Leaves are deeply cleft at the apex and base, producing a twin leaf (butterfly wing) effect. Trees are partially deciduous (some leaf drop begins to occur in fall around the time flowering begins, but some leaves will persist to varying degrees throughout winter).

Genus name honors 16th Century Swiss botanists and herbalists Johann Bauhin and Gaspard Bauhin (i.e., named after identical twins in reference to the bi-lobed leaves unique to genus plants).

Hybrid name honors Sir Henry Blake, plant enthusiast and governor of Hong Kong from 1898 to 1903, and his wife Lady Edith Blake.

Problems

No serious insect or disease problems. Chinese rose beetle will chew on foliage.

Garden Uses

For tropical to sub-tropical areas. Street or shade tree. Ornamental planting. Line driveways. Good cut flower for vases or bowls.