Secret ingredient: Water spinach

MISTAKEN IDENTITY: Water spinach is often confused with Kale, but the two plants are completely unrelated.
MISTAKEN IDENTITY: Water spinach is often confused with Kale, but the two plants are completely unrelated.

These spear-shaped leaves are hugely popular in Thailand, making an appearance in practically every curry, soup and stir-fried dish.

WHAT IS WATER SPINACH (Ipomoea aquatica)?

Water spinach is a semi-aquatic member of the morning glory or convolvulus family from South-east Asia. Although widely used throughout the region it's particularly popular in Thailand, where the distinctive spear-shaped leaves and crunchy hollow stems appear in practically every curry, soup and stir-fried dish. Along with snake beans and belligerently bitter pea-eggplants, water spinach is part of the holy trinity of essential Thai vegetables.


Water spinach has a mild, slightly mineral flavour, a little like watercress (one of its many synonyms is Siamese watercress) without the mustard-like piquancy. Cooked water spinach leaves are very tender with a texture akin to spinach. The crunchy stems exude a slightly bitter milky sap and contrast nicely with the sweet neutrality of the leaves.


Water spinach can be found at Asian supermarkets with fresh produce sections and many weekend markets. too. Depending on the nationality of the vendor it may be labelled as 'ong choy', 'kangkong', 'phak bung', 'water spinach', 'water morning glory' or just plain 'morning glory'. Regardless of who's selling it or where, water spinach is generally offered in neat little bunches that require little if any preparation.

Water spinach can also be grown at home from seed or stem cuttings that will form roots within a day or so if placed in water. Grow in containers set into deep trays of water. While it likes growing in full sun water spinach should never be allowed to dry out. Drain and refill water weekly to prevent mosquitoes from breeding. Pick frequently to keep the leaves tender and sweet.


Although rarely essential to the success of a dish, water spinach imparts a certain authenticity and interest to South-east Asian cooking. Young spinach and silverbeet leaves (de-stemmed) are quite passable substitutes in most situations.


As is true of most leafy greens, water spinach should only be added to hot dishes at the very last minute before serving. The idea is to wilt the leaves, not to cook them - which will destroy texture, flavour and nutritional value. The raw leaves can be shredded and added to larb, yum and other Asian-style salads

Red Curry of Roast Duck with Water Spinach and Lychees

½ Chinese roast duck (available from Asian supermarkets and Hong Kong BBQ shops)
oil for cooking (not olive)
1-2 Tbsp Thai red curry paste
1 can coconut milk
3 or 4 fresh kaffir lime leaves
2 star anise
1 cup hot water
2 Tbsp brown sugar
1 can lychees (drained)
1 tsp pickled green peppercorns (optional)
2 Tbsp fish sauce
1 large bunch water spinach

1. Pull the duck meat from the bones, tear into bite-sized pieces and set aside.

2. Heat a little oil in a deep pan and quickly sauté the curry paste, taking care not to burn it. Add the coconut milk, lime leaves and star anise. Boil rapidly, stirring continuously until the oil starts to separate.

3. Add the hot water, sugar and lychees. Bring back to the boil for 2-3 minutes.

4. Add the fish sauce and the peppercorns, if using. Check taste and add more sugar or fish sauce to suit.

5. Discard the lime leaves and star anise. Add the duck meat and simmer briefly to heat through.

6. Add the water spinach, count to 20 and serve immediately with jasmine rice.


Virgil Evetts is a member of the New Zealand Guild of Food Writers. Follow his adventures in food, gardening and urban farming here.