In the Fullerton Arboretum 
by: Alfredo Chiri
MALABAR CHESTNUT ­ Pachira aquatica ­ Bombacaceae
Donated by: CRFG/Haluza and planted in 1992 (r.f.-04)

Common names: Malabar chestnut, Guiana chestnut, Zapoton, Pupumjuche, Saba nut 

The Malabar chestnut is not a true chestnut but is related to the silk floss tree. It is native to Central America and northern South America. It is cultivated in many tropical regions, including Southern California. In the wild it is a tree that grows in freshwater swamps and alongside rivers.

The Malabar chestnut is a spreading tree that grows to 50 feet in the wild, but in home cultivation it grows more like a large shrub. It has greenish bark with large glossy leaves and creamy white flowers. The flowers emerge from long buds. The petals curl back to the base of the flower, leaving the spectacular cluster of three to four inch off-white stamens. They are followed by oval-shaped woody pods, which may reach 12 inches in length and 5 inches in diameter.

The fruit is an oval pod with pointed ends resembling the kapok or silk floss seed pods, but the seeds inside are nuts, very tightly packed within and very tasty. The pods enlarge until they burst, and the nuts fall to the ground. 

The nuts must be harvested as soon as or just prior to their falling. The seeds or nuts are boiled in hot water. The boiled nuts will have a boiled potato flavor. 

The longer the fruit remains on the ground, the more bitter the nuts will become, making them almost impossible to eat. In some cases it has been found that, depending on the area where the tree is growing, the nuts will always be of bitter flavor.

In many countries the wood of the Malabar chestnut tree is used in the manufacturing of vault ceilings or church domes.

The young leaves, in some areas, are cooked and eaten as a vegetable. 

The Malabar chestnut plants can be easily started from seed and will root from cuttings. It grows in locations protected from drying winds. The tree should be fertilized frequently during the growing season. This tree seldom needs pruning and may be grown in full sun to partial shade.

The Malabar chestnut will tolerate brief exposure to temperatures as low as 28º F, but may drop some leaves.

This particular plant at the arboretum has suffered frost damage from time to time, as can be seen if you look at the lower trunk. Common sense would suggest keeping the plant on the dry side during the cold weather, something difficult to do in some California winters.