Return to Library Home Page

Scientific: Bauhinia variegata
Common: purple orchid tree
Family: Fabaceae (Leguminosae)
Origin: China, India (naturalized across southeast Asia.)

Pronounciation: Bow-HEN-ee-a var-a-ee-GA-ta

Hardiness zones
13, 18-23
USDA 9-11

Landscape Use: A spring flowering accent or specimen tree for mesic or oasis-like landscape settings. Does not perform well in xeric landscapes that have a predominance of inorganic rock mulch.

Form & Character: Upright, rounded, subtropical, Spanish or oriental architecture, vulnerable.

Growth Habit: Mostly evergreen, woody, perennial broadleaf tree, briefly deciduous in early/mid spring, moderate to 20- to 35-feet height with equal spread.

Foliage/Texture: Orchid trees have rounded light green two-lobed leaves, strongly emarginated, that are up to 3-inches wide. In Phoenix, the leaves age prematurely each summer because of the extreme heat and usually become marginally necrotic during later summer and fall if they are not planted in mesic or green surroundings with plenty of supplemental irrigation. Purple orchid tree has a medium coarse texture.

Flowers & Fruits: Orchid tree produces an intense array of large white, pink to purple tubular orchid-like flowers in terminal clusters while the tree is briefly deciduous during early spring; fruit is an elongated, ugly brown pod to 6-inches long during summer.

Seasonal Color: Flowers are profusely displayed from early March through mid April.

Temperature: Heat-loving (except for those scorching Phoenix summer days when the air temperature rockets above 113oF), hardy to 22oF.

Light: Full sun to partial shade.

Soil: In central Arizona, desert alkaline soils will cause leaves to develop interveinal chlorosis caused by iron, zinc, and mangenese deficiencies. This is especially aggrevated by chronic wet, poorly-drained soil conditions. Apply micronutrient fertilizers, especially those in chelated form, in early spring to correct this problem. Orchid tree performs best in soils covered with turf or organic-based mulches.

Watering: Apply water at frequent and regular intervals especially during the summer.

Pruning: Purple orchid tree needs pruning and staking when young to promote structural integrity and a strong scaffold branch system if a single trunk tree is desired, elevate canopy base.....but don't raise the crown too high as trunk sunscald will occur!

Propagation: Cutting or seed

Disease and Pests: None of significance. Local desert stressors on this tree are more from unrelenting abiotic factors such as summer heat, drought, and supraoptimal soil temperatures caused by impervious surfaces (concrete and asphalt) and inorganic surface mulches.

Additional comments: Orchid tree is an excellent small- to medium-sized flowering accent tree that tends to look ragged and tattered when fruiting. Also, orchid tree sheds a moderate amount of litter, but the outstanding spring floral display easily compensates this issue. In Phoenix, orchid trees tend to struggle if placed in landscapes with a dominant inorganic surface mulch cover, such as decomposing granite or gravel rock. The cultivar 'Candida' has outstanding white flowers.

Orchid tree has somewhat smaller leaves and flowers and a more refined appearance compared with its robust and landscape loud cousin, Bauhinia x blakeana (Hong Kong orchid tree).