Landscape March 2014 L-26

Expanding Tree Diversity in Hawai‘i’s Landscapes: Hong Kong Orchid Tree, Bauhinia blakeana

John Edward Montoya1 and Richard Criley1 1Department of Tropical Plant and Soil Sciences

he striking color and fragrance of the Hong Kong orchid tree make it a great addition to the landscape. TheT small to medium semi-evergreen tree grows up to 40 feet tall, with a spread of 20–25 feet, and its fallen flowers cover the ground in a beautiful pink carpet. The Hong Kong orchid was discovered in China. It was a chance hybrid between two species, Bauhinia purpurea and B. variegata, making it sterile. (Taxonomists have since removed the × preceding the species name). It was named for the wife of the governor of Hong Kong.

Recommended Use in Landscapes • Street or shade tree • As an accent or a screen • Garden specimen

Distribution • Originally from Hong Kong, now one of the most popular flowering trees in the world

Propagation Techniques • Cuttings from softwood and semi-hardwood • Air-layering

Cultural Requirements and Tolerance • Pruning required to prevent dense branching • Planting with a barrier to the tradewinds allows for a lush crown • Heat and wind tolerant • Moderately drought tolerant

Published by the College of Tropical Agriculture and Human Resources (CTAHR) and issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in co- operation with the U.S. Department of Agriculture, under the Director/Dean, Cooperative Extension Service/CTAHR, University of Hawai‘i at Mānoa, Honolulu, Hawai‘i 96822. Copyright 2011, University of Hawai‘i. For reproduction and use permission, contact the CTAHR Office of Communication Services, ocs@ctahr.hawaii.edu, 808-956-7036. The university is an equal opportunity/affirmative action institution providing programs and services to the people of Hawai‘i without regard to race, sex, gender identity and expression, age, religion, color, national origin, ancestry, disability, marital status, arrest and court record, sexual orientation, or status as a covered veteran. Find CTAHR publications at www.ctahr.hawaii.edu/freepubs. UH–CTAHR Expanding Tree Diversity in Hawai‘i’s Landscapes: Hong Kong Orchid Tree L-26 — Mar. 2014

Flower and Fruit Characteristics • Flowers fragrant and a showy bright purple color • Flowers throughout the year, more heavily during winter months • No fruit produced

Leaf Characteristics • Ovate to hoof-shaped or bi-lobed • 3–5 inches long • Alternate

Advantages for Use in Landscapes • Does not produce messy fruits • Root system is not intrusive • Weed Risk Assessment score: -7

Disadvantages for Use in Landscapes • Susceptible to the Chinese rose beetle, although it does not cause significant damage • Requires supplemental watering until established • High level of pruning required; when pruned it puts out multiple shoots that then need to be thinned out

Acknowledgements The authors thank Amanda Birnbaum for the many photographs she contributed to this publication.

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