Wèngcài de jīng shì kōngxīn de, suǒyǐ hěnduō rén jiào tā kōngxīncài.
Water spinach has hollow stems, which is why many people call it 'hollow-heart vegetable'.
Tips
usage
蕹菜 is the standard name and the usual one in the south. Most people, especially in the north and online, say 空心菜; Cantonese speakers also say 通心菜. The English name ong choy is the Cantonese pronunciation of 蕹菜.