Water Spinach
Ipomoea aquatica
Water Spinach (Ipomoea aquatica), also known as Kangkong, Ong Choy, or Morning Glory, is a fast-growing semi-aquatic vine in the Convolvulaceae widely cultivated across tropical Asia as one of the most popular leaf vegetables. Thriving in waterlogged conditions where few other vegetables grow, its tender hollow stems and arrow-shaped leaves are a staple green from India to Indonesia.
• A member of the morning glory family — the same family as the sweet potato
• Grows in water and wet soil — one of the few vegetables that thrives in flooded conditions
• Called "kangkong" in the Philippines and Indonesia, "ong choy" in Chinese, "pak boong" in Thai
• One of the most commonly consumed vegetables in Southeast Asia
• The hollow stems are crisp and crunchy, even after cooking
• In some regions, it is classified as a noxious weed due to its aggressive growth in waterways
Taxonomy
• Cultivated across tropical Asia for centuries — possibly millennia
• Widely grown throughout India, Southeast Asia, China, and Indonesia
• Introduced to Africa, the Pacific, and tropical America
• Has become naturalized and sometimes invasive in tropical waterways worldwide
• The genus Ipomoea contains approximately 500 to 600 species
• In the United States, it is prohibited or restricted in several states as a potential invasive species
• A cornerstone of Southeast Asian cuisine and agriculture
Stems:
• Hollow, trailing or floating, 2 to 5 meters long
• Green to purplish-green, smooth, producing roots at nodes
• The hollow stems are crisp and crunchy — a prized culinary texture
Leaves:
• Long-petioled, cordate (heart-shaped) to hastate (arrow-shaped), 5 to 15 cm long
• Bright green, smooth, with entire or slightly wavy margins
Flowers:
• Funnel-shaped (morning glory type), 3 to 5 cm across
• White to pale pink with a darker pink to purple center
• Solitary or in small clusters at leaf axils
• Open in the morning
Roots:
• Fibrous, produced freely at stem nodes where they contact water or mud
• Allow the plant to spread rapidly across water surfaces
Seeds:
• Small, brown, hairy, produced in ovoid capsules
Per 100 g raw leaves and stems:
• Energy: approximately 19 kcal
• Protein: 2.6 g — relatively high for a leafy green
• Carbohydrates: 3.1 g (including 2.1 g fiber)
• Vitamin A: significant amounts (beta-carotene)
• Vitamin C: good source (20 to 55 mg)
• Iron: notable amounts (1.5 to 2 mg)
• Calcium: good source (70 to 100 mg)
• Phosphorus and potassium
• Contains flavonoids and phenolic antioxidants
• Good source of dietary fiber from the stems
Planting:
• Plant stem cuttings directly in wet soil or shallow water
• Space 15 to 20 cm apart
• Can also be grown from seed
Site:
• Requires constant moisture — grows in standing water, ditches, ponds, or very wet soil
• Full sun to partial shade
• Any fertile soil — very adaptable
• Tropical temperatures (25 to 35°C)
Care:
• Essentially no care required once established in wet conditions
• Grows extremely fast — can be harvested every 2 to 3 weeks
• Fertilize with compost or nitrogen-rich fertilizer for best leaf production
Harvest:
• Cut stems 10 to 15 cm above the base — plants regrow rapidly
• Harvest every 2 to 3 weeks in optimal conditions
• Young stems and leaves are most tender
• Stir-fried with garlic and fermented bean paste — the classic preparation across Southeast Asia
• In Filipino cuisine: adobong kangkong (braised in soy sauce, vinegar, and garlic)
• In Thai cuisine: pad pak boong (stir-fried morning glory) with oyster sauce and chili
• In Chinese cuisine: stir-fried with fermented tofu or garlic
• In Vietnamese cuisine: in canh chua (sour soup) and as a raw vegetable with dipping sauces
• In Indonesian cuisine: in gado-gado and plecing kangkong
• Added to curries, noodle soups, and hot pots
• The hollow stems stay crunchy even when cooked — a unique textural quality
• Can be blanched, steamed, or added to soups
Fun Fact
Water Spinach holds a unique legal status in the United States — it is classified as a Federal Noxious Weed and cannot be imported, transported, or grown without a permit in many states, even though it is one of the most commonly eaten vegetables in Southeast Asia. The contrast between its status as a beloved food and a prohibited weed makes it one of the most controversial vegetables in American agricultural law.
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