“The Fifteen Dollar Forest” - moso bamboo, Phyllostachys edulis
In March 1999 the Waikato Branch of the NZTCA had a field trip to Peter Cave's amazing nursery, near Cambridge. Among the wonders in his garden was a grove of the moso bamboo, Phyllostachys edulis. The thought of having fresh bamboo shoots for our stir fries appealed to Nena and me, but knowing how invasive bamboos can be we asked Peter about how difficult moso was to manage. He assured us that if you didn't want to eat the newly-emerging shoots each Spring all you had to do was give them a good kick and that would take care of them. Although still a little suspicious (we had dealt with unruly giant bamboos before, and a friend been battling one that sent its shoots under his house and up through the floor boards), we decided to take the risk, and bought a single plant of the moso variety from him for $15. It was a delicate little plant (probably from a seed collected during one of Peter's SE Asian expeditions); we planted it in the middle of a paddock near our gate, and waited patiently for it to mature sufficiently for us to start harvesting the sought-after shoots.
The next couple of years were a definite anticlimax - the plant did produce a few more stems, but these were dainty miniatures only two or three feet high. We dug out one of these and planted it in another paddock on the opposite side of the driveway. For the next year we had two small clumps of graceful-looking but rather nondescript plants barely visible through the long grass, not looking anything like either tree crops or root crops. Then, in September 2002, the quantum leap occurred. We noticed some thick, spear-like shoots emerging through the grass a few metres from the original (and still quite miniature) bamboo clumps. These things were definitely making a statement, clad in tortoise-shell mottled camouflage and reaching skyward at what seemed a very rapid pace. We were in Auckland for several weeks at a time, and what had been barely visible one week was a metre or more higher when we came back the next. The moso was indeed on the march!
It was then that I started to do some research on this grass that was transforming itself into a tree (and hopefully a tree crop) at a somewhat frightening pace. I found out that moso (also known as kikko-chiku) is highly esteemed in China and Japan as a food source (the very young shoots - more about these in a minute), a source of timber for building and decorative purposes -- the mature culms (trunks) are used extensively in construction, as well as in handicrafts, furniture and papermaking -- and for its aesthetic properties. It is also a source (through its leaves and the sheathes of the emerging spears) of some very important compounds with anti-cancer and anti-arthritic properties, both directly and also indirectly (by facilitating the action of other drugs). The shoots may also have anti-oxidant properties.
The shoots of most bamboos, including moso, also contain taxiphyllin, a cyanogenic glycoside which, if swallowed untreated will result in cyanide poisoning of the consumer! Shoots of some species of bamboo have so much cyanide that the Australian government has forbidden their commercial production. Nevertheless Australia is rapidly developing a bamboo industry aimed at the Asian market, and growers are turning increasingly to moso as the variety whose fresh shoots are in greatest demand. The glycoside in moso and other bamboos is broken down and rendered harmless by heat, and the bamboo shoots that are poisonous when raw will be safe to eat if boiled or steamed for 20 to 40 minutes. If they taste bitter, it's a sign that there's still cyanide present - either cook them some more, or throw them out! The younger the shoot the less cyanide it will contain. Exposure to sunlight accelerates the production of the glycoside, so growers who want slightly larger shoots can inhibit it by covering the emerging shoot with a bag. However the best-flavoured shoots are the young spring (September-November) ones picked just as they are breaking through the surface, or (best of all) the winter crop of dormant subterranean shoots picked from May to August. They are well worth the trouble of boiling - the make an excellent addition to a stir-fry or even a vegetable in their own right, with a taste highly reminiscent of asparagus. There are also opportunities to tap into export markets (and probably local markets too) for fresh shoots. They have to be really fresh, though. Like figs, bamboo shoots are not "good keepers". If you need to store them more than a day or so it's best to can or bottle them.
Our single plant has now grown in to a mini forest, quite literally. On the northern side of the driveway (the grove illustrated in the photograph) it now occupies about 500 sq. m. It didn't start off as a grove. It's sometimes called the intelligent bamboo, as it seems to have the knack of seeking out land where it will do well - for the first couple of years it was on the march it spread in a fairly narrow north - south band from the headquarters clump, and then colonized selected tracts of rich, moist soil east and west of that. The colony in the other paddock behaved similarly once it also sprang into life a year later. After four years of this advanced development the northern grove resembles the set of "The House of Flying Daggers", although the culms are still only an average of about 7 or 8 metres high - when fully mature, the forest can have trunks rising to 25 metres. Each year the height of the canopy of leaves increases, as does the width of the culms. They taper at the base and towards the top, with a fairly uniform several metres in between. At chest height, our 2002-3 culms are 2-3 cm in diameter, the 2003-4 ones 3-4 cm, the ones that matured earlier this year about 5 cm. on average, and this years lot will be slightly wider (and taller) again. The interesting thing about the culms is that they shoot out more or less fully formed as far as their width goes; the horizontal expansion takes place when they are developing underground - as you can see in the photograph, the dormant shoots are quite small and slender, shaped a bit like the Placostylus (püpü harakeke) snails of the Far North.
When they first appear above ground the new shoots are covered with the mottled sheathes; when they get to about 2 metres high these begin to split and reveal the smooth green stems underneath. When the culms are about four years old, they start turning a beautiful golden colour. It's at this stage that they are fully mature and ready for harvesting for timber and other uses (although you don't have to harvest them; individual culms will go on living quite happily for ten or more years). "Branches" (i.e. the leaf stalks) emerged from the stem at about the 4 foot mark on the first set of serious culms in our lot, and progressively further up the stem in each succeeding year. Last year's lot don't branch until well above the 2 metre mark, and this year's are going to be even higher, so you can wander through the grove virtually unobstructed. The leaves are very fine, and make a graceful canopy letting in plenty of light. They also make an excellent leaf-litter, and the "forest floor" is covered with a rich compost, to the delight of worms and other beneficial soil organisms. The new shoots grow quite quickly - seeming to pop 5cm or so above the surface overnight, then grow rather slowly for a week or two until they reach the 30 cm mark, after which they really take off, quickly picking up to 30 or 40cm a day after that. Unless there is a lot of heavy rain - they do not like wet feet, and the smaller shoots may just cease growing and collapse if there's a week of really wet weather, Waikato style, just at the point at which they'd normally make the great leap upward.
However, whether you are planting moso for fun or profit (I wish I'd planted more, earlier, instead of spending hundreds of dollars on mostly unproductive olive trees), you must keep in mind that Peter Cave's assurances notwithstanding, they are invasive. So put them somewhere where they can run riot without wrecking your or your neighbours' peace of mind. Once they get going they increase exponentially. Today I noticed that in a 2 sq. metre area colonized by three culms last year, 7 more shoots, each already over 3 metres high, have appeared and there are more poking through the surface. It looks like the same thing is happening in the less extensive grove (as of last week) in the other paddock. Culms may be quite widely spaced at first, but after a few years they will start popping up quite close to each other, from 5 to 50 centimetres apart. Even at 3 metres high, the new shoots are easy to push over. Nonetheless, the stolons which support them may be burrowing on for many metres distant - the tip of one in the photograph was 2 ½ metres from the nearest visible shoot, and I have pulled up others which have ventured even further. However they don't seem to like to cross over roadways or tracks that are used regularly (maybe the compacted soil puts them off). Commercial growers seem to use deep ditches or barriers to keep them penned up. Fortunately they are not very deep rooted so in our sandy soil it's a reasonably straight forward task to take care of the symptoms. However you have to remember that you are dealing with a huge network of stolons, the parts of which can function autonomously, and of course those that are left can send out new side shoots in what seems like a matter of moments. The mature culms and stolons are also very tough - you need a good saw, a very sharp spade or a powerful pair of loppers to deal with them.
The plants flower at irregular intervals, somewhere between 20 and 80 years. Every plant derived from the same source is likely to flower at the same time (there must be a clock incorporated in their DNA). It would be important to remember this if you wanted to go into moso production commercially. When they flower, the energy of the entire plant network goes into that, and it can be weakened so much that afterwards every culm dies. This doesn't always happen, but at best it will take several years for the groves to regenerate. This is because everything derived from a single seedling is really just one plant. The real trunk of the moso is the underground network - the culms are in effect branches of a single tree. It would therefore be wise to plant a number of seedlings (each of which will have a different flowering time) rather than clones of the same plant if you wanted an uninterrupted supply of bamboo for an indefinite period.
There are quite a few useful scientific and popular accounts of moso and its uses on the web (try "Phyllostachys edulis" or "moso" on Google or AltaVista), and two informative and beautifully illustrated articles in the February 2000 and February 2004 issues of Growing Today magazine, if you want to explore this very interesting and promising topic further.
Richard Benton
Benton, R. (2005) The $15 forest. NZTCA Waikato Branch newsletter. A condensed version was published in TreeCropper Issue 45