Sesbania grandiflora, known commonly as the Agati Sesbania or West Indian Pea is a tree that is a member of the bean family, Fabaceae. Its young leaves are sold in bundles as a leafy vegetable in supermarkets and markets in the Little India vicinty as it is a vegetable that is popular amongst the Indian community here. The flower buds and tender fruit pods are eaten in salads, curries and soups. The leaves, flowers and roots of Sesbania grandiflora are medicinal. Wood from this tree is used to make floating fish nets, paper and fuel.
Not a commonly grown streetscape tree here, Sesbania grandiflora can be used as an ornamental shade tree. It produces large beautiful flowers in pendulous clusters. I have seen two varieties, namely, one with white flowers and another, with red flowers. The flower buds of the white flowered variety were sold in Thailand as a vegetable. These two varieties can roughly be told apart via their young, non-woody stems – the red flowered variety has reddish stems while the white flowered one has greenish stems.
According to the Plant Resources of South East Asia (PROSEA), this tree is also grown as a living fence and to provide support as a trellis for crops like pepper and vanilla, and for the reforestation of eroded areas. Although plants may be pruned back for harvesting of leaves for food or to make a fence, it is interesting to note that Sesbania grandiflora does not tolerate frequent, complete defoliation as this will cause them to die away. Initially, the side branches of a tree may be cut, leaving the main growing point untouched. After the tree has reached a height of 3 m or more, the leader can be cut back to heights above 1.5 m. Indeed, there is a proper way to prune this plant.
The exact origin of Sesbania grandiflora is not known, although India or Indonesia have been suggested. It is now widely grown throughout the tropics.
Sesbania grandiflora is usually started from seed and young plants exhibit rapid growth. They can reach a height of 2 m in just 12 weeks, 4 to 5 m in one year and about 8 m in 3 years, if grown in the ground under suitable conditions. It starts to flower when the plant is about 1.5 m tall. Like many other legumes, this plant has the ability to improves soil fertility by fixing nitrogen in the soil. It has been documented that its ability to fix nitrogen may be suppressed by soilborne nematodes or high soil acidity. At my workplace, I have noticed that em>Sesbania grandiflora is a host plant of the common grass yellow butterfly (Eurema hecabe contubernalis). The caterpillars of this species of butterfly also feed on a range of plants from the bean family.
Sesbania grandiflora is a hard-core tropical tree as it thrives in the lowland tropics, up to 800 m above sea-level. It is frost-sensitive and cannot tolerate cool temperatures over an extended period. A very versatile tree, it can be grown in a wide range of soils including those that are poor or waterlogged as it can tolerate flooding over long periods. It tolerates saline and alkaline soils and has also some tolerance to acidic soils down to pH 4.5.