Introducing the Nam-Nam Tree

The nam-nam is an uncommon fruit tree in Singapore. It grows as a shrubby, much branched shrub or tree which can grow up to 15 m tall. Botanically known as Cynometra cauliflora, it is believed to be a native of Malaysia and can only be found in the cultivated state in South East Asia, Ceylon and Western and Southern Peninsular India. In Malaysia, this tree is mainly found planted in rural villages.  The plant can be planted in pots where it stays small by regular pruning to turn it into a bonsai or an ornamental tree in an outdoor garden. I have recently planted a specimen at HortPark’s Fruit and Vegetable Garden.

Interestingly, this tree is a member of the bean family, Fabaceae. Each leaf on this tree is made up of two leaflets and they form a dense crown, growing from distinctly zig-zag twigs. Each leaflet is shiny smooth, dark green above and paler below. What is extremely attractive about the nam-nam tree is that its new flushes of leaves are bright pink in colour, which contrasts against the largely green background of mature leaves. They hang from the branch tips like handkerchiefs!

Its flowers are rather small and they are produced on the trunk in clusters. Such a habit is often term as cauliflory (and hence the species name cauliflora) which refers to plants that flower and fruit from their main stems or woody trunks rather than from new growth and shoots. Jackfruit is another common tropical fruit that is produced in the same way. For nam-nam, a sackcloth is said to be used to wrap around the trunk to protect the developing pods against rodents and fruit borers and this wrapping does not seem to hinder the progress of flowering and fruit set.

The fruits of the nam-nam are flat, kidney-shaped pods. Like most legume pods, the fruit of the nam-nam has a dividing line but the fruit does not split open readily. The young fruit is very sour but the acid content is observed to decrease with maturity of the fruit. The mature fruit is picked when the skin has turned yellowish brown. It is cooked with sugar to make sweets (compote). It can also be made into a fruit salad, picked, or be used to prepare a special ‘sambal’(a condiment based on pounded chili). The fruits are reported to have useful medicinal properties too and are used in folk medicinal preparation. The seeds yield oil which is used in India for the treatment of skin diseases.

Namnam grows well in wet tropical low lands such as Singapore. From information available on Plant Resources nof South East Asia (PROSEA), experience in India suggests that it is more fruitful in monsoon climates with a distinct dry season. This plant prefers full sun but tolerate shade and a well draining location.

The tree is always multiplied by seed – note that the seed remains dormant during the first three months. Seedlings are quite slow-growing and only start to fruit when they are about 6 years old. Nam-nam can also be propagated by budding and approach grafting.