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 it's 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 a structurally sound, 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.....we affectionately call this the "French fry effect".

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'.