Ipomoea aquatica Forssk.
(Convolvulaceae – the morning glory family)
common name: Kangkong, Water Spinach
Ipomoea is from the Greek ιψ (ips), a worm, possessive form ιπος (ipos), and 'ομοιος (homoios), like; aquatica is from the Latin aquaticus, living in or by water. Kangkong is the name given to the plant in the Philippines.
This is a semi-aquatic tropical plant whose origin is uncertain, but it is now found throughout the tropics and subtropics. It grows in water or on moist soil, with stems 2-3 m or more long, rooting at the nodes. The stems are hollow and can float. The leaves vary from typically sagittate to lanceolate, 5–15 cm long by 2–8 cm broad. The flowers are the usual ‘morning glory’ type, trumpet-shaped, 3–5 cm in diameter, usually white with a mauve centre, solitary from the leaf axis. Seeds are borne in spherical capsules that hold up to 4 greyish seeds.
Kangkong has a mild flavour and can be used raw in salads, as well as lightly cooked. While preparing the vegetable, it is best to strip the leaves from the stems and slice the stems diagonally. Add the stems first and stir-fry for a minute or so before adding the leaves. Cook only until the leaves are just wilted. The slightly slippery texture of the cooked leaves contrasts well with the firm, hollow stems.
The plant is most commonly grown in east and south-east Asia. Because it flourishes naturally in waterways and requires little if any care, it is used extensively in Malay and Chinese cuisine, especially in rural areas. In Singapore, Indonesia and Malaysia, the leaves are usually stir-fried with chilli pepper, garlic, ginger, dried shrimp paste and other spices. In Penang and Ipoh, it is cooked with cuttlefish and a sweet and spicy sauce.
In Cantonese cuisine, a popular variation adds fermented bean curd. In Hakka cuisine, yellow bean paste is added, sometimes along with fried shallots.
In Thailand and Burma, it is often stir-fried with oyster sauce or yellow bean paste, and garlic and chillis. It can also be eaten raw, for instance with green papaya salad; but there is concern that when plants from this region are eaten raw, they may transmit Fasciolopsis buski, an intestinal fluke parasite of humans and pigs.
In the south of Vietnam, the stems are julienned into thin strips and eaten with many kinds of noodles. Also used as a garnish, it has become a common ingredient of Vietnamese cuisine.
In the Philippines, a dish called adobong kangkong is made by sautéing the leaves and stems in cooking oil, onions, garlic, vinegar and soy sauce. It is also a common leaf vegetable in fish and meat stews such as sinigang. There is also an appetizer called crispy kangkong, in which the leaves are coated in batter and fried until crisp and golden brown.
In South India the leaves are finely chopped and mixed with grated coconut to prepare thoran, a Kerala cuisine dish.
Photographs © Donald Simpson, taken in Picnic Bay 2011