Monday, December 31, 2007

Greetings for 2008

To the five known readers of my blog, I wish a happy new year 2008.

I have been unusually busy during the past couple of months on a consultancy project with a tight schedule of deliverables. The Christmas and New Year break has been a real relief. Before Christmas I was travelling through Chicago, Washington, London and Leiden. It was cold! I am glad that my home is in the tropics and my garden is always green.

Thursday, October 18, 2007

Sichuan cuisine, pandas and pickpockets

I have just come back from a week's holiday in Sichuan Province in China. The autumn colours at Jiuzhaigou were glorious. The food was something else. We did not mind the hot chillies but there was something else in the food that caused our lips and tongues to go numb, like a shot of anaesthetic at a dentist's. It was an alarming sensation for our party of 30 Malaysians. The ingredient turned out to be the fruit capsules of Zanthoxylum piperitum, also known as Sichuan pepper. It is neither pepper nor chilli, but a relative of citrus (family Rutaceae). This is the defining ingredient of Sichuan cuisine. The Sichuan people fry this in oil together with chillies to bring out an aroma reminiscent of lemon and anise. Added to meat, vegetables etc, it provides a distinctive fragrance combined with fiery hotness and a numbing sensation.

We visited the Panda Breeding Centre at Chengdu and discovered why Pandas are so popular. They are slow, clumsy, good-natured and people-oriented. They wrestle with each other in full view of the public and feed on bamboo shoots while sitting in an upright position facing the public. There were many little ones in the nursery. I was busy snapping photos when a pickpocket took my wallet from my back pocket!

China is being rebuilt on a grand scale. The main roads in the cities are the widest I have ever seen anywhere, with 6 lanes for cars, one lane on each side for bicycles and another lane for pedestrians, buffered from each other by trees and shrubs. The public toilets have improved everywhere. There seems to be a great deal of optimism, wealth and youth in the cities.

Wednesday, September 26, 2007


I know very little about sunflowers but because it is an oil-producing plant with pretty flowers, I think it is worth some attention. My first few packets of imported seeds performed terribly. The plants were spindly and the flowers did not contain any viable seeds. Then I bought a robust plant already in flower in a local nursery. This produced some seeds and I raised several dozen plants successfully. However the percentage of seed set ranges between zero and 80%. I have not seen any pollinators. According to the textbooks, most cultivars are self-incompatible. I expect, by selection, to produce plants that are self-compatible, which should then have a high percentage seed set. Simultaneously I will eliminate all weak plants. We will see how many generations are needed to produce strong high-yielding plants for humid tropical conditions. A sunflower generation is about 5 months. An oil palm breeding cycle is about 5 years, so I will have done 10 generations of selection for sunflower in the time it takes to do one generation of oil palm. Sunflowers are way behind oil palm in oil yield per ha, which is why only a maverick like me will work on it. It's the challenge, you see; the horticultural equivalent of computer geeks starting up from a garage.

Friday, September 14, 2007

Review of Tropical Horticulture and Gardening

My book, Tropical Horticulture and Gardening, has been reviewed in Chronica Horticulturae, publi shed by the International Society of Horticultural Science. The review may be of interest to readers of this blog, now suspected to exceed five in number.

Tropical Horticulture and Gardening.
Francis S.P. Ng 2006. Clearwater Publications, Kuala Lumpur.

Review by Prof. Jules Janick in Chronica Horticulture Vol. 47 No 3 September 2007

This is a stunningly beautiful book. Its 361 pages are crammed full of over 1000 colored photographs taken by the author, a Malaysian botanist and former employee of FAO in Rome. The book contains 9 chapters: 1. Plant Domestication, 2. The Knowledge System for Plants, 3. Plant Form and Habit, 4. Ferns and Fern Allies, 5. Gymnosperms, 6. Flowering Plants: Monocots, 7. Flowering Plants: Dicots, 8. Garden Design, and Plants, and 9. Tropical Environment. The bulk of the book are excursions; chapters 4 to 7 are arranged by species within families, all arranged alphabetically, with rather minimal but incisive descriptions that include the origins. The prose is well written and the love of plants as well as botanical and horticultural expertise of the author shines through. The chapter on Garden Design contains images of famous gardens thoughout the world visited by the author. There are over 50 information boxes. This is a coffee table book on tropical plants and gardening that will appeal to temperate horticulturists who wish to get aquainted with the diverse garden flora of the tropics.

Tuesday, August 28, 2007

The jatropha bandwagon

In the past few months there has been a surge of interest in the growing of the physic nut Jatropha curcas for the oil content of its seeds. The plant grows in the tropics on soils too poor for most other crops and the oil can be used as diesal for car engines. This is going to meet rural energy needs in poor countries, help prevent soil erosion, create income for women, etc.

All this sounds familiar. In the 1980s somebody calculated that Africa and other tropical regions were going to suffer a fuelwood crisis. Women were having to walk longer and longer distances to gather fuelwood for cooking meals. Eventually, people would have to spend more time gathering wood than cooking food. Forests would disappear, soil would be eroded, etc. Huge amounts of international development aid money were spent on fuelwood research.

Earlier, in the 1960s, another person had calculated that there was going to be an acute world paper shortage by 2000, putting a brake on the growth of literacy, so large amounts of international development aid money went into the establishment of pine forests all over the tropics.

The pinewood and fuelwood bandwagons each ground to a halt after 10 years and the predicted crises never developed. What makes Jatropha different is that it is not international aid agencies this time, but business corporations that are investing in a crop. The research will presumably be more genuine, but I am sceptical. Too many people doing the same things under top-down direction and repeating the same mantras!

I am all for research on biofuels, but the research should be more diversified, not concentrated on Jatropha curcas alone. This species is only one of many possibilities.

Wednesday, August 01, 2007

Herbal remedies and standards of proof

When I was a boy scout, one of our favourite campfire skits involved a Chinese medicine man and a patient. The patient has an ailment for which the medicine man has a cure, which is a bundle of leaves and twigs. "Boil this in a big pot of water for hours until one cup of liquid remains; drink it and your troubles will be over". This was traditional medicine in our grandparents' time and we thought it was funny.

Last week, I met my old scout troop leader and, at one point, our conversation turned on cholesterol. He had been taking pills for a long time to keep his high cholesterol level down. Then a friend recommended a herbal cure: a bundle of leaves and twigs, to be boiled in a big pot of water for 2 hours, together with dried figs (optional) for flavour. He drank this for two weeks and his cholesterol came down to 4 and has remained so for months without any further treatment. So utterly impressed is he that he has been talking to doctors to conduct medical research on this plant, and cannot understand their total lack of interest.

I explained to my friend that scientific research is very complicated. One is supposed to assemble a large sample of people, divide them into two evenly matched groups, give the treatment to one group, and a bogus treatment to the other. The people in the experiment are not to know which group they have been placed into. The people administering the test should not know either. The volunteers get treatment A or B and only the designer of the experiment know what is in A and B. Then there are tough rules governing the use of humans as test subjects. If you use animals, the rules are almost as tough.

If these conditions had prevailed in the past, Louis Pasteur would not have been able to develop a cure for rabies. Having successfully developed vaccines against various fatal diseases of animals, Pasteur developed what he believed would work against rabies. No one had yet been known to survive rabies. But there was no way Pasteur could have assembled a test group of infected people, some of whom would be given the treatment and some not. So he waited until one victim was brought to him. He administered treatment. The victim survived and Pasteur became a hero. The next victim also recovered. And the next. After that, Pasteur's treatment became the standard treatment for rabies, to the regret of statisticians who feel this is a rotten example of experimental procedure.

I asked my friend to show me the plant. It turned out to be a dark-coloured form of Alternanthera sessilis, a weed of ditches and wet places in many parts of the world. The amount of stems and leaves he gave me was enough to fill a pot 25 cm diameter, to a depth of 7 cm. I added water and boiled it for two hours, topping up with water as necessary. After one hour, I added 200 gm of dried figs (labelled 'dried dates' on the packet, sold in Chinese herbal shops). I ended up with 3 cups of dark-coloured liquid. I drank one cup last night and put the rest in the fridge. I found the drink pleasant but too sweet. 100 gm of dried figs would have been enough.

I have no cholesterol problem so this test was merely to satisfy myself that the concoction is pleasant to drink and harmless (I think I still make sense as I type this). So now I am ready to test this on volunteers with high cholesterol.

Wednesday, July 25, 2007

How to create a tropical rain forest

This is my response to a recent email: "We intend to create a multi-tier tropical rainforest along the riverbank of our (residential and commercial) scheme. We would like to know what trees and palms you would suggest for the first (uppermost) tier. If possible the tree specifications (diameter, overall height etc,) and the planting pattern and distances. What shrubs and plants would be suitable for the lower tiers including ground covers."

The property is located in Malaysia, where the climate supports tropical rain forest. To recreate such forest would be easy given time, say 20 years. But of course in a commercial property they would want it done within 20 weeks.

At the 'One Utama' shopping mall in Kuala Lumper, we were promised 18 months to create an indoor rain forest, but in the end we were able to plant our first trees only after the builders had finished and moved out. Nevertheless, our rainforest was presentable within 3 months. We had an advantage that the big trees we needed were growing close by on the same property and could be transported on a private road, and with their spreading crowns sticking out of the back of the transporter. We did not lop off any of the branches. On public roads this would not be possible.

So the size and shape of the largest trees will depend on what can be transported and the crowns may have to be trimmed. The species that can be transplanted as big trees are not many, and most are species of seasonally dry tropical forests, not of true rainforests. They include Tabebuia rosea, Pachira aquatica, Hura crepitans, Khaya senegalensis, Pterocarpus indicus and Shorea roxburghii.

Before moving big trees, I would advise removing the leaves by hand, leaving only the growing tips and youngest leaves intact. This will slow down water loss while the roots are recovering from transplanting. Wrapping the trunks in plastic sheets may also help keep the trees from drying out. The presence of growing tips will speed up recovery. Tree with big leaves are easier to deleaf than trees with lots of small leaves.

Trees should be spaced with 1m gaps between crowns. It will take a couple of years for the crowns to close up. Under the gaps, put in the smaller trees and shrubs. Fill up the gaps and plant close to get faster effect. Ground covers are sensitive to shade and moisture and each species has its own requirements. Try out different species and replace those that fade out. Palms have difficulty recovering from leaf loss, so keep as many leaves as possible while transplanting.

Sunday, July 08, 2007

Getting rid of garden refuse

All gardens generate refuse in the form of grass clippings, old leaves, pruned branches, and the trunks and limbs of felled trees. A keen gardener is supposed to enjoy turning all this into compost. Not me!

After spending much money and time on rotating compost bins, electric-powered wood chippers, temperature probes and other equipment, I have decided that composting is not how I want to spend time in the garden. Open burning is not an option. Open burning is illegal and it would irritate the neighbours. So I piled up my refuse in a secluded part of my garden and every few months I would pay for it to be carted away.

In the beginning, my pile got bigger by the week. Then after many months, an equilibrium was established. The new stuff I added to the top of the pile was balanced by the stuff disappearing at the bottom of the pile. Then after some years, a change took place and the piles began to shrink faster than I could add material to them. I think what has happened is that the population of organizms in my pile of garden refuse became more and more efficient in breaking down plant matter. Even tree trunks got broken down in a few months to the extent that they could be easily smashed into little chips with a hammer.

What is doing the work? I see mushrooms of many kinds popping up from time to time. There are lots of fat earthworms. Also insects of many kinds. There are centipedes, presumably living on the insects. There must be zillions of microbes. All they need is a diligent gardener to keep feeding them with new refuse . I no longer need to have my garden refuse carted away.

Lately, a friend working for a big property developer told me he had run out of hollows in the property to dump the tree trunks that he had been clearing. He has been clearing the property for years, phase by phase. Now getting rid of tree trunks was becoming a bigger and bigger problem. I advised him to go back to the old filled areas, excavate all the tree trunks with a backhoe machine, and smash them into chips. Then the holes would be available for refilling with new tree trunks. The rotted chips can be spread onto the lawns and gardens they are making.

In the humid tropics, the turnaround time for decay of tree trunks is less than one year; faster if one learns to feed the ecosystem that does the work. All those manuals on composting are impractical in the humid tropics, where it is moist and warm all the time and where the diversity of breakdown organisms is at the maximum.

Sunday, May 27, 2007


Avocado fruits are among the more expensive fruits in Kuala Lumpur and Singapore. The fruits are imported from Australia and sold in supermarkets to expatriates and to the few locals who have acquired a taste for them. The majority of Malaysians and Singaporeans think avocadoes are awfully bland, or just plain awful.

However, in the Malaysian state of Sabah, close to the Philippines, where there is a large population of immigrants from the Philippines, avocadoes are cheap, locally grown, and sold by roadside hawkers. The quality, size and shape of the locally-grown fruits is very variable.

The avocado is native to tropical America, and was introduced to the Philippines by the Spanish in the 1600s. The Philippinos have had 400 years to learn to love the fruit, but according to Burkill's Dictionary of the Economic Products of the Malay Peninsula, it was not love at first sight.

The Indonesians got their first taste in the 1700s. They have learnt to love the fruits, and blend it with palm sugar to make a rich nutritious drink.

Avocados were introduced to Malaysia and Singapore by the British in the late 1800s. British rubber planters often had an avocado or two growing in their bungalow gardens.

In all the books on growing avocados, we are told that single trees will not fruit because they need cross-pollination by another tree. The trees in Malaysia ignore this rule. Single trees often produce good crops of fruits. However, after having experimented with avocados for over 30 years, I can say they are extremely variable in behaviour. I have seen trees begin to fruit at 5 years, trees that did not fruit until after 10 years, trees that never fruited at all in 20 years. Fruits vary in size, shape, colour, smoothness / roughness of the skin, thickness of the flesh, quality of the flesh (creamy, lumpy, etc). A lot of work will have to be done in testing and selection before we can have a good reliable clone for our particular climatic and soil conditions.

To grow an avocado it is best to use a seed from a tree that is proven locally (e.g. known to produce abundant fruit of good quality at an early age). Seeds from another country may produce healthy trees but such trees are likely to be unfruitful.

Tuesday, May 15, 2007

A Malaysian Horticulturist in Florida

Last night, I hosted a visitor from Florida, Charles Teh, who had emigrated to USA twenty years ago. He was practicing as a horticulturist in Singapore and Malaysia before he decided to emigrate. It was interesting to get his impressions of Kuala Lumpur now compared to when he left.

I took him to Desa Park City, a new residential area in Kuala Lumpur, and he thought the standard of landscaping and tree planting was comparable with residential areas in Florida. But he was horrified to see Bucida buceras (native of Florida) as a roadside tree here. He says this is a weedy tree in Forida. In Malaysia, I assured him, Bucida behaves itself and does not multiply on its own.

I was surprised to hear that so many of the plants we grow here are also grown in Florida, albeit with some difficulty in the winter. In turn, he was surprised to see snapdragons, pelargoniums, rosemary and pansies flowering on my balcony. I later took him to a rooftop garden where I have magnolias, persimmons, plums, peaches, apples, planes and camelias growing. We are pushing the limits. While gardeners in temperate and subtropical regions are exploring ways to grow tropical plants, some of us in the tropics are exploring ways to grow temperate plants.

Tuesday, May 08, 2007

A temperate garden in the lowland tropics

Many temperate plants will grow and flower in the highland tropics at 1000m elevation and above. In the Cameron Highlands in Malaysia for example, fuchsias, daylilies, apples, roses, pelargoniums and snapdragons grow and flower throughout the year. In the lowlands e.g. in Kuala Lumpur, at 100m, they survive for only a few weaks or may grow but not flower.

I have been trying to grow temperate plants by arranging for them to get a cold water shower for 15 minutes a night at midnight. The water is chilled to about 18 degrees Celcius. However the effect has not been significant.

My next option was to get engineers to design a flat bed cooler on which I can place containers of plants for their roots to be cooled at night. I have opted for cooling at night so as not to have to fight against the daytime high temperature of 30 degrees. At night there is a natural drop to 24 degrees, which is a help. However the engineers have not been able to design a flatbed cooler for me. I thought this would be somewhat like a mini ice-skating rink, but exposed to sun and rain and only switched on at night. Does anyone out there know whether this can be done?

Friday, April 20, 2007

Where are the plant breeders?

Horticulture thrives on novelty, and plant breeders are the people who create novelties, but breeders barely exist in Malaysia. I am a plant breeder; I breed cannas. I choose to breed cannas because cannas flower all year round and come in many colours and forms. Well-grown beds of cannas are like well-grown beds of tulips, but unlike tulips, they bloom all year round. My friend Gregori Hambali, breeds calatheas in Bogor. Gregori sends his plants to the US to be patented and marketed there by a big horticultural enterprise. None of his plants have ever been released in Indonesia. Having no US backer, I keep my new varieties of cannas to myself. Anybody who buys one canna (or calathea) can multiply it and soon it will be everywhere. I have no wish to spend money taking out patents and then spend more to enforce my patents. Our society is a long way from accepting the concept of plant varieties as intellectual property. I do not believe the newly enacted plant patent laws will encourage plant breeding in Malaysia.

I am trying to get funding by selling varieties for MR 2000 (USD 570) each. Ideally, the buyer should be a local government agency, which has a horticultural use for the plants and would not mind if the plants leak out to the public, as they eventually will. The money they spend is public money after all. I think cannas in Malaysia could be as popular as tulips in the Netherlands and become the flower of the people. New varieties should be bred and distributed freely but the breeder deserves to be compensated, like any public servant except that he is compensated not by salary in advance but by results upon delivery. If only the whole of the public service could be run that way . . .

Friday, April 06, 2007

New ethnobotanic garden in Kuching, Sarawak

I have just been in Kuching to oversee the expansion of the ethnobotanic garden at the Sarawak Biodiversity Centre (SBC). The garden was designed according to my specifications and after one year, the results are terrific!

The garden was designed to display the plants used by the many different native communities of Sarawak. To obtain the plants, expeditions were made to the interior of Sarawak over the past three years. In one particularly tough expedition, I trekked 5 hours in wet weather and fading light to a village called Pa Lungan near the Indonesian border in the Bario Highlands to document and bring out a new species of banana, which we named Musa lokok. Musa lokok is now flowering and multiplying in the ethnobotanic garden, together with some tw0 hundred species of other plants, many of which will be new to science, including begonias, hoyas, orchids, aroids and ferns. Having the plants close at hand and concentrated in one location will allow comparative studies on the biology (growth and reproduction) of Bornean plants on an unprecedented scale. Eventually I expect to have over 500 species within a half-hectare area.

Already, conducted tours have been arranged for schoolchildren. Eventually tourists will be able to visit. The garden is close to the Orang Utan Centre at Semengok.

Thursday, March 29, 2007

1st Review of Tropical Horticulture and Gardening

Three months after publication, the first review of Tropical Horticulture and Gardening has been published. It is by JF Veldkamp and MMJ van Balgooy of the University of Leiden, in the Flora Malesiana Bulletin Vol 14 of March 1007, pages 60-62. Unusually for a joint review, the two authors wrote separate opinions. They pointed out several errors and took issue with the author over several points. But their verdict was favourable. Veldkamp thought my history of plant domestication was 'brief but informative', my introduction to nomenclature 'clear and helpful' and my chapter on morphology 'lucid'. Nomenclature and morphology are what students in botany sleep through in botany class. Of course, Veldkamp and Balgooy are professors, not students, but it is good to know that the professors approve of what I wrote. Balgooy says "In my opinion this is the best and most complete treatment on tropical gardening in SE Asia ever written."
Thank you, thank you.

Sunday, March 11, 2007

Gardening for Beginners

My son John has moved into a new house in Kuala Lumpur. He used to live in a condominium. Now he has land for gardening: a strip in the front and a rectangle in the back. John's neighbours are doing their gardens, and it is interesting to see all the different kinds of ideas being implemented by proud houseowners who are probably gardening for the first time.

John complains that my book Tropical Horticulture and Gardening is of little use to him and other absolute beginners. I have to confess I did not write the book for absolute beginners. I also found that house builders do not provide for gardeners. I had to have a water tap installed at the back, drainage holes drilled through the back wall, and a proper soil mixture spread over the ground, not to mention the stones we had to dig out. We bought stone slabs for a garden path and John laid a path with the slabs arranged left and right in two parallel lines. I told him normal people walk by putting one foot in front of the other, and rearranged the slabs in a single line. For an instant garden, we bought flowering plants at their peak. Among them were the daisy-like Melampodiun paludosum, which, I warned, would only last one or two months, but would produce seeds and seedlings. A month later as the plants started to fade, John complained about the weeds he was having to pull out from the flower bed. The 'weeds' turned out to be seedlings of Melampodium paludosum.

OK, so a book for beginners has to be very different from the one I wrote. Also, Melampodium paludosum is too much of a mouthful, and needs a suitable nickname. Maybe in a year's time we will have something ready for testing on beginners. By that time, John will have graduated to the next level.

Tuesday, February 20, 2007

Seedless fruits

During the past few days we have been celebrating what is called 'Chinese New Year' in Malaysia and Singapore, 'Spring Festival' in China and 'Tet' in Vietnam. In Malaysia and Singapore, lots of mandarin oranges are consumed during this festival. This year I have been struck by the fact that most of the mandarin oranges are seedless. If mandarin oranges can be made seedless, we may expect other citrus fruits to follow.

Of other tropical fruits, we can expect mangosteens to become seedless. Already we have come across the odd seedless mangosteen fruit. Somebody should find a way to convert this rare possibility to certainty. With durians, nangkas, chempedaks and chikus there are trees that produce fewer seeds per fruit as well as fruits with reduced seed size, but we do not know if complete seedlessness is possible. Does anybody know?

Thursday, February 01, 2007

Websites for Tropical Horticulture and Gardening

Tropical Horticulture and Gardening is now listed in the following websites:

Here are comments from some readers
... magnificent... (Susyn Andrews -- horticultural botanist, Kew, England).
... a real treasure of information and eminently readable... (Tan Sri Chong Hon Nyan -- Patron of the Selangor Gardening Society, Malaysia).
... a monumental book... (Prof. Abdul Latif Mohamad, UKM--National University of Malaysia)
... I like it very much. (J.F. Veldkamp, Editor of the Flora Malesiana Bulletin, Leiden, Netherlands)
... a wonderfully useful book, much needed and a complete source of information re tropical horticulture and botany. (F. M. Schlegel, Forestry Consultant, Hochrhein, Germany)

Monday, January 22, 2007

Correction on burnt soil

The bags of burnt soil sold in KL for RM 1.20 per bag actually contain about 5.3 kg of burnt soil, not 3 kg as earlier reported.

Because of the wood-ash mixed into it, burnt soil contains a useful level of potassium, one of the essential elements for plant growth. The word potassium itself is derived from 'pot ash'.

Friday, January 19, 2007

Gardening on tropical clay soil

Clay soils in the tropics are not the ideal medium for plant growth, because clay particles stick together to impede penetration of water and air. On lawns, clay soils get compacted with time, starving the grass roots of oxygen.

Where plants have been growing naturally for a long time, leaves, bark, roots and other plant parts decompose and make the top layer of soil porous. Such top soil is the most fertile of natural soils, but it takes a very long time for new topsoil to form.

Chinese gardeners discovered long ago that the underlying clay soil, if burnt over a wood fire, becomes porous, friable and non-sticky, allowing for excellent water and air penetration. We do not know who discovered the process. For a description, we have R.E. Holttum's account in his book, Gardening in the Lowlands of Malaya, first published in 1953. Holttum was Director of the Singapore Botanic Gardens and Professor of Botany at the University of Malaya.

"The earth is broken up into fairly large pieces, and piled up on top of some old wood and other refuse, into a heap some four feet deep and six feet or more across. A cover to keep off rain is necessary. The stacking of the pile is of course a matter requiring skill. It must allow just enough circulation of air to keep a slow fire burning. The fire is allowed to burn for two days or sometimes more. When the operation is finished, the earth is changed from its original condition of clay to a porous granular state. It will consist of a fair propertion of large pieces, which should not be broken up too small, grading down to dust. The dust is not good for plants that require a particularly well aerated soil, and can be removed if necessary by the use of a fine sieve. The essential properties of the burnt earth are that it will absorb water without becoming sticky, that the lumps do not readily break down when the soil is watered; and that it is sterilized, all pests and diseases and harmful micro-organisms being destroyed. "

Yesterday, I visited a place in Sungei Buloh, just outside Kuala Lumpur, which produces burnt soil. There were about 10 kilns on the site, on leveled ground cut out from a hill side. Each kiln is a square enclosure with sides about 6 ft long. A post is erected at each corner, to support a roof of galvanized iron sheets ('zinc sheets') 6 ft or 7 ft above the ground. Planks are nailed to form walls on three sides. The fourth side is left open for stacking the wood and soil. First, wooden billets are closely stacked on the floor, to form a layer one foot thick, with some gaps for ventilation. Then lumps of clay soil, cut out from the exposed hillside, are laid on top of the wood to form a 2 ft layer. Then another layer of wood is laid on top, followed by another layer of clay. Then the roof is fixed, and the fire is lit. The fire burns for one week, and the pile takes another four days to cool down. The burnt soil, mixed with wood ash, is then passed through a sieve, the purpose of which is to hold back the larger lumps that need breaking down. There is no attempt to remove fine dust.

Burnt soil is used extensive in and around Kuala Lumpur and retails at $1.20 per bag of about 3 kg. At the kilns, it is sold for 80 cents a bag. In Ipoh, 3 hours drive away, it is sold for $2.00. Burnt soil is also produced locally in Ipoh but is said to be of lower quality. The difference, apparently, is that the clay soil in Sungei Buloh contains a good proportion of sand, which makes the particles more friable.

Thursday, January 18, 2007

Identity of Bauhinia kockiana in doubt

Two experienced gardeners, one in Kuching and the other in Singapore, have told me that the name Bauhinia kockiana seems to have been applied to two different species. If there has been a mixup of identities, the only way to sort them out would be to compare the two plants against scientifically authenticated specimens in a herbarium.

The plant illustrated and described in Tropical Horticulture and Gardening is the one that is commonly grown in Malaysia and Singapore, but it only came into the market in the 1990s. It has become very popular because it flowers practically throughout the year.

The other plant is rare but seems to have come into cultivation much earlier. In Singapore, it flowers profusely once a year.

Wednesday, January 17, 2007

Citrus microcarpa on sale early

The first Citrus microcarpa plants are now on sale in Kuala Lumpur at MR 38 - MR 48 for plants about 1 m tall, heavily laden with fruits. Whatever technique they use to stimulate heavy fruit production, it certainly works, for this species as well as for the kumquat, Citrus japonica. The latter has oblong fruits while the former has round fruits. Unfortunately, the fruits are already yellowing and softening, and Chinese New Year is one month away. The timing is off, at least for this batch of plants.

Thursday, January 11, 2007

Chinese New Year and Citrus fruits

The mandarin orange, Citrus reticulata, is in greatest demand during the Chinese New Year when they are served to guests and given away as presents. This custom is particularly strong among ethnic Chinese in Malaysia and Singapore. Mandarin oranges are imported from China. They grow in Malaysia but fruit irregularly and local fruits are considered inferior. In China, they fruit at the right time. Since the date for the Chinese New Year follows the lunar calendar and is out of synch with the solar calendar, and since plant behaviour is believed to follow the solar calendar, I have never understood how mandarin oranges in China 'know' when it is time to ripen.

Another Citrus associated with Chinese New Year in Malaysia and Singapore is the locally grown Citrus microcarpa (known as limau kasturi in Malay and calamondin in the Philippines). The plants flower and fruits irregularly throughout the year, but nurserymen have learnt to manage them so that they flower before the festival and fruits ripen just at the right time. The plants, heavily laden with fruits, are used to as decorations. Most years, the growers get the timing right, but this year is disastrous. I hear that the price for plants has doubled compared to last year because of very poor fruiting. This is blamed on the exceptionally wet weather. It has been raining every day for over a month and there has been serious flooding in many parts of the region.

I have a plant that is growing vigorously in my garden, flowering and fruiting profusely and totally unaffected by the wet weather. It grows in a pot of horticultural carbon. All the excess water simply drains off. Improved drainage may be what the plants need most in wet weather.