(Editor's Note: This article was originally published on May 18, 2008. Your comments are welcome, but please be aware that authors of previously published articles may not be able to respond to your questions.)
If there is a much common plant to be seen on Reunion island and which can be seen from the East to the West and North to South, growing from sea-shores to some 900 meters high (2700 feet) it is not Hibiscus nor Jacaranda but sugarcane, a species very much related to our local history and still the number one crop here. So let us check this ‘sweet reed'.
Botanically called Saccharum officinarum, the sugarcane belongs to the very large family of the Graminae, just like grass, bamboos, corn and rice. But contrarily to the cereals which are grown for the seeds, the grains, sugarcane is produced for its thick stem full of saccharose. Classified in the sub-family Panicoids (2500 species!), the sugarcane belongs to the tribe Andropogon like sorghum which stems also are quite rich in sucrose.
So, this is a giant weed which will grow to two or five meters (six to fifteen feet) high with stems two to five cm across, regularly divided by nodes on which are found buds and latent buds, forming thus the internodes. Those internodes are usually ten to fifteen cm long but can be thirty depending on the variety and growing conditions (soil, sun, watering, fertilizing...). Sugarcane can be yellow, green, white, purple, violet, striped, although nowadays commercial crops rely on modern hybrids, usually yellow or purple with rather non poetic names such as R570 widely grown on Reunion as it suits both local soils and climates.
Researchers now agree that the geographical origin of this plant is New-Guinea from where it was first spread in Oceania and South-East Asia by human migrations during the tenth and fifth century before present time. From there it went to India where Alexander the Great discovered it during one of his raids in 326 BC and called it ‘the sweet reed which gives honey without bee's help'. Brought to Mediterranean by Persians around year 510 it was soon introduced by the Arabs in Egypt, Northern Africa and Southern Spain during the seventh century. Spanish and Portuguese conquerors exported it first to Africa and later to Latin America during the fifteenth century. It is nowadays grown in all tropical and subtropical areas, the most important producers being (by annual tons); Brazil, India, China, Pakistan, Thailand, Mexico, Australia, Colombia, Cuba and the USA.
It is a cold-sensitive plant (it will stop growing when temperatures are under 15 to 18°C and will die at 0°C) which grows in many kinds of soils but will prefer loose ones, the yearly water requirements are around 2000 to 3000 mm and it does require manure or potash fertilizers to ensure a good crop. It is propagated by means of cuttings three or four internodes long which are simply laid in a furrow and covered with soil and watered. The first shots will be seen four to six weeks later depending on heat and humidity. A grown clump will produce ten to fifteen canes. Those clumps are to be renewed on a regular basis, usually every three years but a clump in the garden can be kept for years on. Maturing depends greatly on local weather, it will be eight to nine months in Louisiana but may take eighteen to twenty-two months in South Africa. Harvest will start in winter, July-August on Reunion, February in the Northern hemisphere as the sugar level rises with dryness, lower temperatures and shorter day-length. Huge machines have been designed for the job but as they are good only on very level ground the machete is still a much used tool which can also be turned in a very effective argument to settle disputes...
An important botanical detail regarding sugarcane is that it belongs to C4 group while most plants belong to C3. Do not worry, this has nothing to do with transgenic plants or any other modern witchery, it just means that C4 plants produce chemical compounds with four carbon atoms while the other one will make three carbon atoms molecules. The result is on one hand a faster growth because of more carbon input (keep in mind that plants use gaseous carbon from the air which is under carbon dioxide form) and on the other hand a strong elimination power of this same CO2; an hectare of sugarcane can absorb 60 tons of CO2 per year and produce 42 tons of oxygen (this is probably why we breath so well on Reunion...)
Let us go back now to the scientific name of sugarcane, until the 17th century it was claimed to hold medicinal properties and doctors would prescribe doses for a number of troubles, the word ‘officinarum' indicated the apothecary dispensary and what it contained. No need to study medicine for ten years to know how acts sugar on people.
Besides being a nice desert to chew on it will also enforce your gums and clean your teeth and a nice clump of sugarcane has a quite decorative effect in any garden especially if you are lucky enough to find some old varieties such as the ‘Tamarind', ‘Batavia', ‘Bois-Rouge', ‘Mapou' or ‘Rat Gros-Ventre'.