Water spinach, or swamp spinach, grows abundantly in tropical regions in Southeast Asia and is used extensively in cuisine in places such as Vietnam, Malaysia, the Philippines, and Indonesia. This ingredient works great in stir-fries, soups, and other dishes where a mild, green flavor would benefit a recipe.
What Is Water Spinach?
Despite its name, water spinach is not really spinach, nor is it related to spinach. It's also not part of the brassica family, so it's also unrelated to kale and its bitter leafy green ilk. Instead, water spinach is part of the morning glory family and has long vine-like stems and bell-shaped morning glory-like flowers. Ipomoea aquatica is known as kangkong in the Philippines, kangkung in Indonesia and Malaysia, rau muong in Vietnam, pak bong in Laos, and trakuon in Cambodia. Its English names include water or swamp spinach; sometimes it's referred to as Chinese water spinach, or ong choy in Cantonese.
Water spinach is a semi-aquatic plant that thrives with little or no supervision. In fact, it grows so quickly that it is considered invasive in some regions in the U.S. where it has been introduced, but in Southeast Asia where it is used to cook myriad dishes, water spinach is never invasive. On the contrary, it is perceived as a culinary blessing because it grows so easily and is therefore sold very cheaply.
There are many varieties of water spinach; some are shorter than others and the leaves are of different lengths and shapes. All, however, have hollow stalks from which the leaves grow. Both stalks and leaves are eaten. Water spinach is used in stir-fried dishes or added to soups.
How to Cook With Water Spinach
Because it is difficult to determine the sanitary conditions of the water in which the vegetable grew, it is not typically a good idea to eat water spinach without cooking it first. To prepare it for cooking, rinse very well to remove any sand or grit trapped in the stalks and leaves. Cut off and discard the first couple of inches of the stalks. This portion is too tough and fibrous.
After discarding the unwanted parts, take the bunch of water spinach and cut it in half horizontally. The lower half, consisting mainly of the stalk, will require a longer cooking time so it is best to separate this portion separate from the leafy and more tender upper half. It may take a little practice to find the right interval of cooking time, but once you get the hang of it, you will be able to enjoy water spinach cooked just right in soups, stir-fries, curries, and the like.
What Does It Taste Like?
Although it's not related to spinach, it does taste a bit like a cross between spinach and watercress. It doesn't, however, have the slightly earthy taste and bitter bite that spinach can have.
Water Spinach Recipes
Water spinach can easily be used in place of spinach, especially its cooked applications, or in recipes that require cooked watercress, such as soup. It also takes well to ingredients that give it flavor, such as garlic, ginger, chili pepper, and shrimp paste.
Where to Buy Water Spinach
You can find this item sold in bunches, like spinach, in some grocery stores, farmers markets, and in Asian specialty stores in the United States. Use the typical guidance about buying greens to check for freshness—signs of wilt, yellowing, or dampness indicate a shorter shelf life once you purchase it.
The USDA has classified it as a noxious weed because it grows so fast in aquatic environments in warmer climates that it tends to crowd out other species. (It also means you can't import or transport water spinach between states without a permit). Its harvesting is permitted, however, under specific conditions such as greenhouses and well-irrigated fields in the United States. It's grown in places whose weather conditions can support it, such as California, Texas, Florida, and the U.S. Virgin Islands, and often near Asian-American communities.
Water spinach will keep in the fridge much the way any leafy green would, in a sealed container with a damp paper towel for several days. It's best to not wash before you refrigerate the spinach, as this can make it wilt quickly. Wash it right before you intend to cook with it.
Nutrition and Benefits
Water spinach contains a fair amount of vitamins A, B6, and C, along with magnesium and fiber. The plant has been considered medicinal in Asia for hundreds of years for its laxative effects and has been studied for its use in India as a treatment for lead toxicity.
Davanjee S, Dua T, Das S. Water Spinach, Ipomoea aquatica (Convolvulaceae), Ameliorates Lead Toxicity by Inhibiting Oxidative Stress and Apoptosis. PLoS ONE. 2015;10(11):e0143766. doi:10.1371/journal.pone.0139831