Bangkok's boiling streets not best for bird's nest ferns

These graceful epiphytes need an appropriate environment in order to thrive, and being attached to small trees in full sun along smog-laden roadways doesn't fit the bill

It's Songkran, the Thai New Year, marked by Buddhist ceremonies and an exodus of people going back to their home provinces to be with their relatives and loved ones. The exodus began on Thursday so Bangkok's usually busy streets are now almost empty of traffic. But if you go out on an errand today expect to be drenched with water, as it has become a tradition for playful people to splash water on passers-by or on one another as part of the merriment. In the provinces especially, pick-ups ply the streets loaded with drums filled with water and youngsters on a water splashing spree, all in the name of fun.

PLEASING PORTABLES: Potted bird’s nest ferns make a beautiful addition to any garden.

In the sweltering summer heat drenching can be a welcome relief, not just to people but also to plants. Spare, therefore, a thought to the plants along the streets; splashing water to mark Songkran will have a more meaningful sense of purpose if you aim the water at these plants as well. I am thinking about bird's nest ferns (Asplenium nidus, known in Thai as ka luang) attached to small trees along Bangkok's streets in particular. Exposed to the hot sun, fumes from passing cars and heat emanating from the pavement, they are a sorry lot at this time of year, and most other months, for that matter.

Bird's nest ferns really should not be on street trees at all. Perhaps someone had seen trees festooned with ferns along the streets of Singapore so he hatched this brilliant idea of having ferns along Bangkok's thoroughfares, too. Bird's nest ferns are a sturdy lot, but they also need an appropriate environment in order to thrive, and being attached to small trees in full sun is certainly not it. Although they are happiest attached to trees, these must be big trees with lots of branches that would shelter them from the sun and provide humidity. Unlike Singapore, Bangkok's streets do not have many such trees.

bird’s nest ferns are happiest attached to big trees like these.

Few other plants can be reminiscent of murmuring brooks and cool tropical forests than ferns. In their natural habitat they can be terrestrial and found in the ground along streams and under trees; lithophytes growing on moss-covered rocks; or epiphytes attached to the branches and barks of old trees. Whether terrestrial, lithophytes or epiphytes, they prefer a place with high humidity such as that found in forests. Some species, however, can easily adjust to conditions in city gardens and bird's nest fern is one of them. An epiphyte in its natural habitat, where sometimes it is precariously perched along branches of trees attached to nothing but a vine or two, the bird's nest fern makes a very beautiful potted plant.

Bird's nest fern got its common name from its simple and broad, ascending fronds that form a nest or basket. This basket of fronds catches dead leaves that fall from the tree which bears the fern, and these accumulated leaves slowly decompose to provide nutrients for the plant. The leaves also form a covering for the top of the fern's stem, which produces new fronds at the centre of the basket. The young fronds at first grow vertically upwards through the decaying debris and then bend backwards, holding the decaying leaves firmly between their bases and the bases of the preceding fronds next to them.

The stem underneath the basket of fronds is covered with large, spreading roots , each with a woolly covering of root-hairs and growing in a mass of decaying leaves and old frond bases. This part of the plant is much like a sponge that holds a large quantity of water. Because of this, it is a favourite rooting place for other plants, mostly other epiphytic ferns.

The bird's nest ferns on Bangkok's streets may have been propagated by tissue culture, which explains their uniform size. But this does not give the Bangkok Metropolitan Administration, or the people in charge of planting trees on city streets, the licence to expose them to lethal surroundings. It is like sentencing them to life in hell, where the conditions are so harsh that death is a better option.

Bird's nest ferns add beauty and a verdant touch to any garden. They can be planted in pots or hanging baskets, using decomposed leaves and chopped coconut husk as the planting medium. For best results place them where there is bright light but not direct sun. Keep the sponge-like base of the plant moist by watering the whole plant. The water caught in the nest of fronds will trickle into the sponge-like base and watering is not needed again for a day or two.

For a robust specimen, feed your plant a water-soluble complete fertiliser (NPK 15-15-15 or 16-16-16 or equivalent) once a month or every two months. Feeding the plant is like watering; using a sprinkler or a sprayer, drench the whole plant with the solution.


Email nthongtham@gmail.com.

Left, New fronds grow at the centre of this newly planted bird’s nest fern in Bangkok, above.

Right, bird’s nest ferns are a sturdy lot, but attaching them to small trees along Bangkok’s streets is like sentencing them to life in hell.

About the author

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Writer: Normita Thongtham
Position: Writer