Pronounciation: Bow-HEN-ee-a bla-key-A-na

Hardiness zones
Sunset 13, 18-23
USDA 9-11

Landscape Use: Spring flowering accent or specimen tree, mesic and oasis landscape design themes only. Hong Kong orchid tree is NOT a tree for desert, xeric or water-conserving Phoenix landscapes. But sometimes its a great tree to sit under and take a quick siesta nap after eating a lunch plate full of carnita tacos and drinking two mid-strength beers.

Form & Character: Upright and rounded, full, robust, colorful, subtropical, complements Spanish or oriental architecture.

Growth Habit: Briefly deciduous during the fall, woody, perennial broadleaf tree, moderate growth rate to 20- to 40-feet tall with slightly greater spread.

Foliage/texture: Rounded, light green, two-lobed leaves or strongly emarginated, larger than foliage of Bauhinia variegata; coarse texture.

Flowers & fruits: Large, white, pink to purple tubular orchid flowers in terminal clusters; sterile, mildly fragrant, occassionally producing elongated pods without viable seeds.

Seasonal color: Spectacular flowers are displayed sporadically during late fall, but mostly during spring.

Temperature: Heat tolerant (except for those scorching Phoenix summer afternoons when the air temperatures soar past 110^oF) only when planted within the midst of a "green" landscape (lots of surrounding landscape vegetation or afternoon shade protection by the built environment), cold hardy to only 28^o to 30^oF.

Light: Full sun to partial shade, limit western sun because trunks and branches are prone to sunscald damage if exposed.

Soil: In Phoenix, interveinal chlorosis in alkaline soil is a common occurrence that requires sometimes annual applications of micronutrient fertilizers, preferably during early spring.

Watering: Not drought tolerant, apply water at frequent and regular intervals especially during the warm summer months.

Pruning: This spectacular tree is especially difficult to train when young because of its tendency to grow long, arching (floppy) and somewhat brittle branches. It needs a well thought out strategy for training (aka pruning and staking when young) to promote an upright and tree-like form when mature. Mature trees should never be aggressively pruned (aka crown raised or crown thinned) because of their inherent sensitivity to sun damage on trunks and branches.

Propagation: Softwood cuttings, air layering or grafting of woody stem tissue.

Disease and pests: Spider mites, trunk heart rot.

Additional comments: This is a spectacular flowering tree with large, light purple pink orchid flowers. It is somewhat more frost and heat sensitive than its landscape cousin/hybrid parent, Bauhinia variegata, and is intolerant (to the point of death) of being surrounded by impervious surfaces (asphalt and concrete) and/or inorganic surface mulches (decomposing granite or gravel rock).

The bottom line: Sorry sustainable hippies, Hong Kong orchid tree is not for xeric landscapes or water conservation efforts.

Taxonomic tidbit: As the genetic research about Hong Kong orchid tree taxonomy is inconclusive and it is only known in cultivation, this tree is also seen in the literature as a named cultivar, Bauhinia 'Blakeana'.