Indochina dragonplum

A large evergreen tree 15–30 m tall with a straight rounded trunk that can reach about 1.5 m in diameter in mature trees, with buttresses at the base; the bark is grey and fairly smooth and the wood pinkish-brown. Leaves are odd-pinnate, 30–45 cm long, with 5–7 pairs of ovate-oblong, entire leaflets. Small greenish-white bisexual flowers form panicles 10–23 cm long at the tips and axils of branches, blooming in April–May. The fruit is a flattened spherical drupe about 2 cm long and 2–2.5 cm across; green and sour-fleshed when young, yellow when ripe. The hard, flattened stone bears five oval pits on its upper face that resemble a human face — the origin of the Chinese name renmianzi (“human face”).

Native to Indochina and southern China: northern and central Vietnam, Laos and Cambodia, together with Guangdong, Guangxi, Yunnan and Hainan; it grows in closed lowland forest, usually below 350 m elevation. In Vietnam the sấu tree is the characteristic street shade tree of Hanoi and has long been planted in parks, schools and temple grounds and across the cities of the north. Urbanisation has not reduced its numbers, because the species is planted very widely as a landscape, fruit and timber tree.

Green fruit is rich in organic acids — mainly citric and malic acid — that give its characteristic sourness, together with vitamin C, flavonoids, tannins and pectin; as the fruit ripens the sugar content (glucose, fructose) rises markedly. The leaves and bark contain tannins and flavonoids, and an ethanolic leaf extract was found to be rich in phenolic compounds with antioxidant, antibacterial and in-vitro wound-healing activity (Phan et al., 2025).

In Vietnamese cuisine, green sấu fruit is bruised and sugared into the summer drink “nước sấu”, used in sour soups and braised fish; ripe fruit makes preserves, candied fruit and sấu pickled in fish sauce; Wikipedia notes the fruit is also cooked with duck. In 2021 the first 22-tonne shipment of frozen sấu fruit was exported to Australia (SGGP, 2021). In traditional medicine (HKBU, 2025): the fruit (renmianzi) is sweet-sour and cool, used to strengthen the spleen, promote fluids, quench thirst and relieve hangover and heat, treating poor appetite, febrile thirst and sore throat; the root bark treats breast abscess; the leaves are applied to sores and ulcers. The pinkish-brown timber is used for furniture, boards, posts and rafters.

Sấu fruit is a traditional food that is safe in moderate use; people with stomach complaints may limit it because of the strong acidity, and foraged fruit should not be confused with wild Spondias plums. Preparations from root bark and leaves should follow a practitioner's guidance. On conservation: the species has no formal assessment on the IUCN Red List as of 2026; it remains fairly common within its range and is widely planted as a shade and fruit tree, so it faces no major threat — this site keeps its original Least Concern (LC) status.