Metroxylon sagu Rottb.

A clumping palm. It can grow up to 10 to 70 m high with a fat trunk (50-75 cm across). A palm can have 18-24 leaves which are 5-7 m long. The leaflets can be up to 100 per leaf and 50-160 cm long by 3-6 cm wide. After about 15 years the palm produces a large flower on top, then the palm dies. The flowering stalk can be 5-7 m long. The palm has suckers near the base. Some kinds have fertile seeds about 2-3 cm across on the flower. There is a complete range from very long thorns to short or no thorns on the leaf bases.

A tropical plant. A high water-table is tolerated or required by the plant. Temporary flooding does not appear to affect the crop but permanently flooded sites do not appear to be suitable. Because of the site requirements sago is almost always on locally level ground. The level ground can be a broad flat basin or flood plain or a local depression or stream edge in more dissected terrain. Sago seedlings are hardly harmed, by one rather saline flooding, per fortnight. Sago seedlings can probably withstand a salinity of EC = 10mmho/cm. The maximum altitude is about 1200 m but the optimum is between sea level and 800 m. Sago palms grow well in wet conditions. It can tolerate saline or brackish water. It grows better in well drained than in poorly drained conditions. It grows best with a temperature of about 25°C. It cannot tolerate temperatures below 17°C. It suits hardiness zones 11-12. They are widely distributed in the central and southern Philippines. They are especially abundant in the fresh water swamps of the Agusan Valley in Mindanao. They also occur in Papua New Guinea and Indonesia.

The bud can be eaten cooked. Sago starch can be processed from the pith. The sap can be collected for a drink called “tuba” in the Philippines Sago grubs are often cultivated and eaten.

Suckers or seedlings are planted in fresh water swamps or along creeks. Once stands are established in swamps, they continue to re-grow from suckers. Plants are thinned by removing some suckers. Some “seeds” will not grow but those that are fertile need to be planted as soon as they form because they loose their viability. Seeds germinate within 3 weeks. To plant sago, the planting site near a creek or in a damp place, is first cleared of trees and rubbish. Then a sucker of a suitable variety is chosen from an old sago clump. Often the fronds of the sucker are up to 3 m high. It is first checked to see if the sucker is old enough. Suckers ready for planting have a tough woody connection to the base of the old palm. It is also checked to see that fresh roots are being produced from the base of the sucker. A suitable sucker probably has fronds 3-4 m long and is about 1.5 years old. This is chopped through with an axe. The sucker is then simply taken to a new site and planted in a shallow hole 30 cm x 30 cm x 30 cm. If several palms are being planted, they should be about 7 m apart. The only other attention the new palm needs is an occasional weeding to cut back rubbish when it gets too thick. If a suitable seedling is available it can be replanted where it is wanted. Several informants estimated that approximately 50% of transplanted suckers died. The suggested reasons were either choice of an immature sucker or climatic variability, especially drought. (Because of a general lack of awareness of disease organisms by Papua New Guinea farmers, these should not be ruled out.) If a seedling palm, as opposed to a sucker, was available for transplanting, it was considered to be equally suitable. Apart from walking time and site clearing, if needed, the work involved in planting a sago took about 10 minutes. Once planted the sago groves renew themselves through suckers and an almost permanent stand is produced. The optimum spacing is considered to be 275 clumps per hectare. In most naturally established stands this would be thinner than that which occurs. It is also considered that for one clump thinning out suckers so that 3 suckers only of different ages were maintained to give optimum harvestable yield. Higher yields per trunk reduce the amount of labour involved in processing the pith. The type of site chosen was just marginally too damp for gardening of annual vegetables, but not permanently inundated It takes 12 to 15 years for a sago palm to grow big enough to cut down. Palms in poor soil grow more slowly. Normally, one main trunk grows up, but several small suckers may shoot up around the base. Sometimes these suckers spread out and the space between the palms becomes crowded. Too much competition between clumps slows down the growth of the main palm, so the grove needs to be thinned out. This is very easily done. A small hole (10 cm x 10 cm) is cut with an axe into the top of the trunk of a sucker that is not wanted. This hole lets the sago beetle in and the sago grubs which develop quickly kill out the sucker. They don't get into the main palm or other suckers unless a hole is made. After a few months when the sucker is seen to be dead it can be split open to provide a feed of sago grubs. There is no simple way of telling when a palm is ready to harvest. By experience people learn to recognise how big each variety should be before it is ready to harvest. If the palm were left too long it would produce a very large flower at the top and then die. This flower would use up all the starch in the trunk so that there would be nothing to harvest. As long as the flower has only started to grow and the seeds haven't yet formed on it, the palm is still suitable for harvesting. Sometimes when people are in a hurry to use a palm which isn't quite ready, they cut a hole to check how much starch is stored inside. But sago grubs must not be allowed to get in. It is considered that improvement in predicting the time for harvesting could be made by choosing trunks with at least 50 leaf scars on the trunk, with short internodes between the leaf scars and with a higher circumference. After the palm has been cut and harvested another sucker grows more quickly than the others and becomes the new main trunk. It still takes about the same time to get mature. On some soil types such as where there is a clay pan and the soil is regularly flooded the palm can take up to 10 years longer to reach maturity.