Kwai Muk (Artocarpus lingnanensis or A. hypargyrea) is closely related to Jackfruit. It is native to Southern China, where it grows above 150 metres altitude. It is a slow-growing, erect tree to 10 metres, with attractive long slender leaves. Its dark green foliage makes it an attractive landscaping tree.
Kwai Muk produces small round fruits which have a velvety, yellow-brown skin, and orange to red flesh. The fruit may range from seedless to about 7 small seeds. These fruits are about 2.5 – 5 cm across (golf ball sized) and are acid to subacid and said to be refreshing and of excellent flavor. They can be eaten fresh when fully ripe, or can be dried, or preserved. The trees can be propagated from seed.
In Queensland, the fruit ripens from February to April. Tiny yellow male and female flowers are produced on the same tree, the females in globular clusters about 1cm long. Two trees may be needed for good fruit production. It is similar to mango and jak fruit in cold hardiness, with mature trees being able to survive about -4°C. It is relatively wind hardy.
Jenny Awbery and Daleys website