This species has been cultivated as a food crop for many hundreds of years and, in that time, several quite distinct forms have arisen. The nomenclature of these forms is confused, to say the least, and by no means universally accepted. We have followed the treatment used by GRIN, though it is very likely to be revised in the future[].

Common Name: Rosette Pak Choi

General Information

Rosette pak choi is an annual to biennial plant developed in cultivation from Brassica rapa. Growing from a non-fleshy taproot, it forms a rosette of leaves up to 20cm tall from which eventually arises a flowering stem up to 5cm tall.
Rosette pak choi is widely cultivated in China for its edible leaves[].

Known Hazards

The oil contained in the seed of some varieties of this species can be rich in erucic acid which is toxic. However, modern cultivars have been selected which are almost free of erucic acid.

Botanical References

Range

A cultivar of garden origin

Habitat

Not known in the wild.

Properties

Edibility Rating
Habit	Biennial
Height	0.15 m
Pollinators	Bees, Self
Self-fertile	Yes
Cultivation Status	Cultivated

Cultivation Details

Rosette pak choi has been developed in cultivation in the temperate zone of China. It can be grown as an annual from the temperate zone to the tropics and can also be grown in the cold season in the temperate zone, where it can tolerate temperatures down to around -10°c and can even be harvested from under the snow[]. The plants are less likely to stand up to prolonged winter wet[]. The prostrate forms are hardier than semi-prostrate forms[].
Succeeds in full sun in a well-drained fertile preferably alkaline soil[]. Prefers a pH of 5.5 to 7[]. Prefers a cool moist reasonably fertile soil[]. The plant is shallow rooted and intolerant of drought, it responds well to a moist fertile soil but succeeds in poorer soils than standard Pak choi[].
There are several named varieties[].
It is slower-growing than standard Pak choi, Brassica rapa chinensis[].

Edible Uses

Leaves - raw or cooked[]. They can be eaten at any stage from seedling to mature plant[]. The leaves are tougher and stronger flavoured than standard Pak choi[]. The flavour is enhanced after a touch of frost[]. The leaves are said to be very nutritious, with up to twice the mineral content of Pak choi[].

Immature flowering stems - cooked like broccoli[]. A sweet flavour[].

An edible oil is obtained from the seed.

Medicinal

None known

Other Uses

None known

Propagation

Seed - sow in situ mid summer. Spring sown crops are prone to run quickly to seed if there is a spell of cold weather[]. Some varieties can also be sown in a cold greenhouse in autumn or early spring to provide leaves overwinter and in late spring.