In the jungle, they are a mixed blessing. While they provide a rooftop bridge, a flyover used by creatures from ants to lemurs and monkeys, they derive nutrients including sunlight and water at the expense of trees, and increase arboreal distress. At worst they can strangle their hosts. And they can be huge. One jungle bauhinia in Surinam was measured at over 600 metres.
No such giants will invade your garden. Most, if not all, domestic vines have been hybridised in order to produce more conspicuous and more colourful flowers. In the process, much of their inherent vitality has been lost. Nonetheless, we still look to climbers to cover man-made eyesores, or add a natural look to bare walls, trellises or buildings.
One of the easiest to cultivate is the Bengal clock vine, a climber which still grows wild in parts of Southeast Asia. A member of the Thunbergia genus, it has a twining habit, which means it is self-supporting. The pale pink or white blooms are borne on hanging stems which hang down in front of heart-shaped foliage. Outpacing most shrubs with its rate of growth, the clock vine will cover a wall or tree trunk in a matter of months. Propagated by cuttings, it is an ideal starter for the new garden. One fine local example is at ‘WE Café’ on Chao Fa West Rd. The trellised walkway is completely enveloped by a vine which welcomes guests with an ever-present display of pendulous blooms.
The Rangoon creeper (Quisqualis indica) also thrives in local conditions. Of all the cultivated climbers, it is arguably the most spectacularly floriferous. Hence my decision to put a photograph of it in full bloom on the cover of my gardening book. The first time I encountered it, the vine was draped over a high boundary wall, replete with masses of vibrant, trumpet-shaped flowers in profuse clusters of white, pink and red. It stretched for a full 20 metres. Amazingly, it is still there today. Originally the vine grew wild in secondary forest in Burma (Myanmar) and the Philippines, but horticulturalists soon recognised its value as a garden shrub.
In the dry season, quisqualis erupts into full flower fed by earlier monsoon rains that have already given the bright green foliage a lush appearance. The flowers, in technical parlance, are terminal racemes and have a distinctive feature: the buds open white or cream, turn pink on day two and then red on day three. Rather like the blooms of the cotton rose (hibiscus mutabilis) which undergoes the same visual mutation in one day, with quisqualis, all three colours appear in the same cluster, delicately poised at the end of slender stalks. And as an added benefit the blooms are gently fragrant.
Very easy to cultivate, The Rangoon creeper has extended its influence and become naturalised in certain parts of the globe, though not in Thailand. It prefers slightly acidic soil which may present a problem in the alkaline conditions one often encounters in newly developed plots. If this is the case, a few spadefuls of loam or compost should help.
There is only one downside: the vine is not reliably self-supporting and though its long branches quickly become woody (ligneous), they are often not robust enough to support unaided the heavy tresses of flowers. Pruning may help, but it is better to provide ties on bare surfaces such as walls.
The third member of this lusty trio is the passion flower, or passiflora edulis. It takes its name from the floral arrangement of its uniquely exotic flowers, which are said to resemble elements of Christ’s passion. One of the most rampant of climbers, mine competed successfully for years with a bougainvillea. Because it is, unlike quisqualis, a tendrilous vine, it can utilise any structure, natural or otherwise ‒ for support, and in the right conditions, can attain a height of three metres. The large, 10-petalled flowers (up to 10cm across) are utterly distinctive, and range from the bluish white of cerulea, to the commonest hybrid, edulis, which sports white blooms shading to lavender, with a dramatic blue or purple crown.
Most, though not all varieties, also produce attractive and edible fruit which is marketed commercially as a drink. Round and hard, they begin green and turn yellow or even purple. The seeds from decomposing fallen fruit will often germinate.
All varieties are especially vigorous climbers, with lots of lobed, deep green leaves. Generally unfussy about soil conditions, in common with most tropical vines, they will bloom more profusely in sunshine. Above a trellis, they will form a dense canopy. Pollinated primarily by harmless carpenter bees, these purple-black insects will arrive in numbers once they are aware of a passiflora in the vicinity. Not a bad choice… for man or bee.
Patrick Campbell’s book ‘The Tropic Gardener’, described in one Bangkok review as the best book on Thai gardening for 50 years, is available for B500 (half price) to personal callers from 59/84 Soi Saiyuan 13 in Rawai (Tel: 076-613227 or 085-7827551).