Bauhinia bowkeri Harv.

Family: Fabaceae (Pea & Bean Family / Leguminosae)
Subfamily:
Caesalpinioideae (Caesalpiniaceae)
Common Names:
Kei White Bauhinia, Bowker's Bauhinia, Keibeesklou, umDlandlovu (Xhosa)

Bauhinia bowkeri


LeafBauhinia bowkeri is a much-branched, scrambling, woody shrub with a graceful arching habit that can reach a height of 5-6 m. The bark is greyish-brown. The leaves, like all South African bauhinias, are distinctively butterfly-like and consist of two rounded, nearly semi-circular lobes fused along the inner margins as if on a hinge. In this species they are deeply bi-lobed, divided for about two-thirds of their length, and 10-40 mm long x 20-50 mm wide on petioles approx. 15 mm long.

The Kei bauhinia flowers profusely during spring and summer (October to December). The flowers are carried in bunches along the branches and at their tips, each bunch consisting up to 6 individual strongly sweet-scented flowers.Buds, flowers and pods Long slender buds are enclosed by a brown calyx that splits to the base along one line only to release the flowers. Each flower is ±40 mm long with smooth, pure white wavy petals, ten fertile stamens on ±30 mm long filaments, and a style tipped with a greenish stigma. The calyx persists, becoming maroon-brown streaked with greenish-cream on the outside and greenish-cream on the inside. It encloses one side of the base of the flower and after the petals have dropped, it tops the developing seed pod, eventually drying and shrivelling up. The pods are woody, dark brown, up to 150 mm long, straight and narrow, splitting explosively at the sides along its entire length, to release flattened circular approx. 10 mm diameter seeds during late summer to autumn. The woody spiral remains of the previous season's pods often remain on the bush for some time.

Bauhinia bowkeri is a rare endemic of the thicket or valley bushveld region in the Eastern Cape. It occurs along the Mbashe River margin between Umtata and Butterworth, where it is locally common and sometimes occurs in dominant stands, often in rocky ground. The soil is fertile and the climate is hot. Frost is rare, but mild if it does occur. Rainfall is mainly during the warmer summer months, ranging between 800 - 1250 mm per annum, and winters are dry.

The genus Bauhinia was established by Linnaeus in 1753 and commemorates the brothers Caspar and Johan Bauhin, both botanists and herbalists, the characteristic paired leaves being a reflection of their relationship. Bauhinia bowkeri was first collected by Colonel James Henry Bowker (1822-1900), a farmer and soldier, but also a naturalist and an authority on butterflies, who collected the specimen near Fort Bowker on the Mbashe River in the Eastern Cape. The Afrikaans common name beesklou (cattle foot) is applied to most of the bauhinias and refers to the resemblance of the leaf to the spoor (footprint) of cloven-hoofed animals. The prefix Kei (rhymes with the greeting "hi") refers to the region along the east coast of South Africa on both sides of the Kei River, roughly from East London to Port St Johns.

Many of the almost 300 species of Bauhinia are popular garden subjects because of their decorative foliage and ornamental flowers and are widely grown in sub-tropical or tropical regions of the world. Most bauhinias are woody shrubs, some climbing with tendrils or scrambling and some are small trees. The most commonly cultivated is Bauhinia variegata, the orchid tree, originally from India and China. There are seven bauhinias that are indigenous to southern Africa, and all show horticultural promise. The most well-known and widely cultivated is the pride-of-De Kaap, Bauhinia galpinii, bearing masses of bright orange-red flowers in summer. There is also the yellow bauhinia or bosbeesklou, Bauhinia tomentosa, a large shrub or small tree with bell-shaped yellow flowers; the Kalahari white bauhinia or koffiebeesklou, Bauhinia petersiana, a scrambling shrub or small tree with very crinkled white flowers which is divided into two sub-species Bauhinia petersiana subsp. macrantha which has broader petals, a smaller habit and occurs in north-western parts of South Africa, Namibia, Zimbabwe and Angola, and Bauhinia petersiana subsp. petersiana, which is usually a small tree and occurs in north eastern Zimbabwe, Mozambique and northwards; the KwaZulu-Natal white bauhinia, Bauhinia natalensis a dainty shrub with bell-shaped white flowers; and the pink bauhinia or sandbeesklou Bauhinia urbaniana a shrub or bushy tree with rose-pink flowers from north-eastern Namibia. After the pride-of-De Kaap, Bauhinia bowkeri is the most striking and although still uncommon in cultivation, it is gaining popularity.

Growing Bauhinia bowkeri

Closeup of flowerBauhinia bowkeri is best planted in fertile, well-composted soil in a sunny, well drained position and thrives in warm dry gardens especially in the bushveld and thicket regions of South Africa. It is a drought tolerant shrub that also grows well in the winter rainfall Western Cape, where it should be watered occasionally during the dry summer months. It is tolerant of a wide range of soils and is suitable for most gardens where frost is not too severe. It re-sprouts vigorously when pruned. An annual compost dressing or mulching during late winter is highly beneficial. Once established, it is a long-lived shrub flowering profusely during spring and summer. Bauhinia bowkeri can be grown as a solitary specimen or in groups. It makes a good screening plant and is well suited for growing against fences and embankments.

Planted against gabion At Kirstenbosch we have them planted against the gabions in the nursery where they are doing very well. A gabion is a large galvanised wire mesh basket filled with stone that is used to stabilise an embankment. The wire mesh is intended degrade with time with the idea that soil and debris will fill the gaps between the stones and plants will eventually take over the function of holding the bank in place. Plants that are adapted to growing on cliff faces, as well as those with a tendency to scramble or an ability to cling are planted above, below and between the gabions and trained to grow right up against them. Other plants well-suited to this function include Ficus burtt-davyi, Pavetta lanceolata and Bauhinia galpinii.

Bauhinia bowkeri is easily propagated from seed sown during spring or summer, planted 1-2 mm deep in sandy well drained potting soil, placed in a warm position and kept moist. Germination should occur within 3 weeks and the process can be speeded up by soaking the seed overnight in warm water. To prevent pre- and post-emergence damping off the seed should be treated with a fungicide prior to sowing, or watered with a fungicide immediately after sowing. The Kirstenbosch nursery has had good results with many members of the Fabaceae that are especially prone to pre-emergence damping off by dusting the seed with Apron 35 SD (active ingredient: metalaxyl). The seedlings should be potted up into individual bags/pots as soon as the first pair of true leaves appears, and care should be taken to avoid damaging the developing tap root. The growth rate of the seedlings is medium to fast and flowering can expected within 5-8 years.

References:

  • Ross, J.H., Flowering Plants of Africa, Plate 1816
  • Coates Palgrave, Keith, 1977, Trees of Southern Africa, First Edition, C. Struik Publishers, Cape Town, Johannesburg.
  • Palmer, E. and Pitman, N., 1972, Trees of Southern Africa, A.A. Balkema, Cape Town.
  • van Jaarsveld, E., 2000, Wonderful Waterwise Gardening, a regional guide to indigenous gardening in South Africa, Tafelberg Publishers, Cape Town.
  • Leistner, O.A. (ed.), 2000, Seed plants of southern Africa: families and genera, Strelitzia 10., National Botanical Institute, Pretoria

Ernst van Jaarsveld & Alice Notten
Kirstenbosch National Botanical Garden
December 2001


 


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