– Yu Choy Sum
– Yau Choy Sum
– Yu Chai Sum
Yu choy and Yu Choy Sum are sold as different vegetables; choy sum refers to the young, tender vegetable hearts, but yu choy can be grown to produce a larger, less tender vegetable. As a general rule, the younger ‘Yu Choy Sum’ stalks are preferred, but larger plants are similar in taste and use.
Yu Choy Sum is a green leafy vegetable similar to Gai Lan, and can be characterized by the distinct yellow flowers which it bears. Each flower has four yellow, oval to round petals with six stamens on fleshy, erect stems which are 0.5 to 1 centimetre (0.2 to 0.4 in) in diameter and 15 to 20 centimetres (6 to 8 in) tall with light to dark green, and are oval (becomes acuminate shaped, or basal-shaped near the flowering stage) with slightly serrated margins leaves, which never forms compact heads like the cabbage.