SEMINOLE COUNTY RESIDENTIAL HORTICULTURIST
This deciduous to semi-evergreen tree belongs to the legume family and characteristically has large, bi-lobed, light green, papery leaves. The orchid tree is native to China and India, but some related species are found in the American Continent. The most splendid of all, the Hong Kong Orchid Tree, is an evergreen sterile hybrid, which produces magnificent reddish-purple flowers. In other species, blooms come in shades of purple, red, pink, white or yellow and can be three to four inches across. Blooming occurs mainly in early spring, but flowers are produced in abundance at various times of the year, depending upon the species.
The tree: The tree has a relatively fast growth rate and reaches 25 to 30 feet of height with a spread of 25 to 35 feet. Unpruned trees form a rounded crown. Its foliage is distinctive and attractive with double-lobed, rounded leaves, light green in color and about four to six inches broad. The deeply cleft leaflets are heart-shaped with prominent veins. Blossoms are very showy and can be produced year round in warmer climates. Flower colors vary from pink, purple, red, white to yellow. The elegant, white stamens add to the beauty of the flowers. The fruit is an elongated pod, 6 to 12 inches long, and brown in color. The fruit persist on the tree for a relatively long period of time. Although the tree is deciduous, it is effective year-round as a shade or an ornamental tree because its blooms appear at the same time that it sheds its leaves.
Species: Bauhinia blakeana, known as the Hong Kong Orchid Tree, which is also the floral symbol of that island, is seedless. It is also the most spectacular and most wanted Bauhinia specie, bearing six-inch, orchid-like flowers of rich reddish or rose-purple during the winter but is very tender to freezing temperatures. Bauhinia variegata, is a very popular specie, produces in winter and spring and has orchid-like blossoms with purplish casts. The cultivar ?Candida? produces white blossoms. Bauhinia purpurea, which is variable specie, produces narrow-petaled, red-purple to blue-purple flowers in late fall and early winter while leaves are on the trees. Bauhinia monandra produces pink, single-stamened flowers all summer. It is commonly known as the Butterfly flower. Bauhinia acuminata also blooms all summer but with white flowers. Bauhinia aculeata, with white flowers, is hardy as far north as hardiness zone 8b but has a tendency to produce many root suckers.
Culture: The orchid tree grows well in full sun or in partial shade. The tree can grow in moist, well drained, clay, loam, or sandy soils, under slightly acidic conditions. A pH range between 5.5 to 6.5 is optimum for good growth. In alkaline soils, minor element deficiencies will produce yellowing of the leaves. The tree naturally develops several trunks and has to be trained to grow from a single trunk. Branches droop as the tree grows and will require pruning for vehicular or pedestrian clearance beneath the canopy. It requires pruning to develop a strong structure. Pruning should be done only after the blooms fade. The Orchid tree can be propagated from seeds, grafting or layering. Chewing insects and borers may present a problem for the Orchid Tree. No diseases are of major concern. Leaf spots and powdery mildew caused by fungi may produce some damage to small trees but should not damage established trees.
Use and Management: Growing best in full sun or high, shifting pine shade, the orchid tree thrives in any well-drained soil. The flowers are followed by many brown, woody, 12-inch-long seedpods that are unattractive on the tree and a nuisance when they drop and seeds germinate. The wood tends to be weak, and sprouts are often seen growing from the base of the tree creating an unattractive landscape. Some people consider the fallen leaves messy because they are large and decompose slowly. In full bloom, orchid trees make a beautiful street tree with their foliage and flowers arching over the road. However, the drooping branches must be removed as they develop, to allow for vehicle clearance beneath. Because sprouts will have to be removed regularly and the tree is bare for a month or two, it is considered by many to be a high-maintenance tree not suited for large-scale street tree planting. It is often used as a specimen and a residential street tree. A rapidly growing tree requires little care once started and should be fertilize annually. It is cultivated worldwide mainly because of its beautiful flowers but its bark is sometimes used in dyeing, and the flower buds are considered edible in India. Many species, cultivars and varieties are available.
All Seminole County Extension Services are Open to all Regardless of Race, Color, Sex, Handicap or National Origin.