Bauhinia plants have beautiful flowers, (they are often called Orchid trees), as well as strange leaves, that look as though two leaves have been joined to form a pair – a distinctive characteristic for many, though not all, Bauhinia species.
The name ‘Bauhinia’ comes from two Swiss-French botanist brothers, Johann and Gaspard, the sons of a French physician, who had fled to Switzerland to escape religious persecution in France.
The younger brother, Gaspard, who taught medicine at the University of Basel in Switzerland, described and published thousands of plants in his “Phytopinax” in 1596. The older brother, Johann, though also a physician, traveled widely in Europe studying plants, and became famous as the result of his work on plant classification, “Historia Plantarum Universalis”, which, however, was not published until 1651, more than thirty years after his death.
The genus was named after the Bauhin brothers in 1754 by Linnaeus, who remarked, “the two-lobed leaves or two as it were growing from the same base” recalled “the noble pair of brothers”.
Bauhinia is a large group, (about 300 species), of shrubs, small trees and climbers, growing throughout the tropical and sub-tropical parts of the world.
In Sabah one of the most beautiful species is the lovely orange- to scarlet-flowered ‘bunga api’ (Bauhinia kockiana) or Fire Flower, that is occasionally seen climbing over trees along rivers or at the edge of forest remnants, and is found not only in Borneo, but also in Peninsular Malaysia and Sumatra.
It is widely grown as an ornamental plant over fences in Malaysia and South-east Asia, and increasingly across the tropics, for it is a fast and vigorous grower.
It flowers in frequent flushes, producing masses of fiery orange with subtle hues, for the flowers are produced over several days, and the colour of each individual flower varies according to its age.
Orange is the most common colour variety, but I have also seen paler and darker forms and even one that is almost scarlet, though this seems rare.
There is also a gorgeous golden-flowered ‘bunga-api’ which we have seen only occasionally, and only in the wild. For some reason it appears that this has never been brought into cultivation and whether it is a new undescribed species, or merely a golden form of the ‘bunga api’ we are not sure, but it is certainly one of the most beautiful of our wild Bauhinias.
It used to grow among the old trees on the side of Signal Hill near the HSBC and the Tong Hing Supermarket in KK, and though I have not seen it flowering for a while, I am hoping it is still there and that the current dry season will encourage it to bloom!
Bunga-api leaf is not lobed!
Interestingly, ‘bunga-api’ is one of the few Bauhinia species that does not have the typically lobed double leaf, and is sometimes referred to the genus Phanera rather than Bauhinia, but its flowers are still those of Bauhinia, with open, spreading petals, easy for bees, wasps and particularly butterflies, to pollinate.
‘Bunga-api’ was first collected sometime between 1831 and 1836, in Sumatra, by the Dutch botanist, Pieter Wille Korthals, who named it after Hendrik Merkus de Kock, the Dutch Vice-Governor-General of the Netherlands East Indies (Indonesia) between 1826 and 1830. The ‘Illustrious’ Bauhinia
The other common species of wild Bauhinia in Sabah is very different. Bauhinia excelsa, also collected by Korthals, (but this time in Kalimantan), is found only in Borneo. It is one of the commonest wild Bauhinias in Sabah, growing over old secondary forest trees, even around KK, and is often seen in forest remnants along the roadside.
‘Excelsa’ means “tall, eminent or illustrious”, and this species is a strong, woody climber, suitable for growing only in large gardens or parks with tall forest trees up which the vine can climb, producing its large inflorescences all over the canopy when it reaches the light.
White and Yellow flowers
The flowers are enclosed and protected in tough buds covered in silky dark-golden hairs. These hairs are also found on the flower petals that open white, turning through cream to yellow as they age. We saw it recently up at the Kinabalu Park, smothering a tree in the Mountain Garden, just below the Liwagu restaurant, with scattered yellow and white flowers. Some forms have have white and red flowers.
Driving to Sandakan from Kota Kinabalu recently, we passed through a patch of what are known as ultramafic soils just after Telupid.
Ultramafic soils are derived from ultramafic rocks, of which there are several outcrops in Sabah. These rocks and soils are generally high in nickel and magnesium, (toxic to plants in large quantities), and low in essential plant nutrients needed for growth, such as calcium, phosphorus and potassium. Many of the species found here are specially adapted to these conditions and will not grow elsewhere, though others seem somehow to manage.
Pure white flowers
Here, scrambling over the roadside shrubs, was another vigorous Bauhinia climber with beautiful pure-white flowers contrasting with its dark, glossy green leaves.
We have seen it nowhere else and so far we have not managed to discover its name.
Small shrubby Bauhinias are occasionally seen in cultivation in Sabah, with white or yellow flowers, but these are introduced.
The Hong Kong Orchid Tree
The commonest Bauhinia in cultivation is the Hong Kong Orchid tree, Bauhinia x blakeana, with striking purple flowers, which has been planted in several places as a street tree around KK.
This plant has an interesting history having been discovered, (according to the Missouri Botanical Garden website), as a single natural hybrid, “collected in 1880 near the ruins of a house along the shore of Hong Kong Island near Pok Fu Lam.
Cuttings were taken by a nearby French mission, with subsequent cuttings taken from the mission trees for inclusion at the Hong Kong Botanical Gardens. This hybrid is not only considered to have the best ornamental flowers in the genus but is also considered to be one of the most attractive flowering trees in the world.
Its parents are Bauhinia purpurea and Bauhinia variegata, both cultivated ornamental trees, but the hybrid itself is sterile and does not produce viable seed, so must be propagated from cuttings and marcots.
It was given the name of ‘blakeana’ in honour of Sir Henry Blake, the British Governor of Hong Kong from 1898 to 1903 and Lady Blake, who enthusiastically supported the Hong Kong Botanic Gardens, and in 1997, a white stylized flower become the centre of the Hong Kong flag.
Neither of the parent species grows in Borneo and though the flowers of the Hong Kong Orchid tree are pretty, they do not flower at their best in our hot, muggy climate, preferring slightly cooler temperatures – the ‘bunga-api’ is a much better choice if you want a Bauhinia in your garden!