Fockea

Fockea crispa was first described by Carl Thunberg in 1794 as Cynanchum crispum and renamed in 1839. Fockea crispa (revised to Fockea capensis) is a popular, easily-grown caudiciform succulent, and its tubers can become very large (e.g. 60 cm). Some authorities regard F. capensis as a variety of F. edulis. The 11 Fockea species found in southern, eastern and tropical Africa have swollen, sometimes warty, tubers, which grow underground in habitat, and branching stems with opposite leaves. The stems readily exude a milky latex (12% rubber) when bruised. However, the tubers of several species are edible and eaten (roasted) by the Hottentots despite the latex, which flows in copious amounts from broken roots of F. edulis. Cooking is reported to inactivate the latex. The small five-lobed flowers have a sweet scent and attract hoverflies.

The sweet-smelling flowers of Fockea edulis are about one quarter of an inch (6 mm) across and a pale cream colour. In England they appear freely in the early Autumn, but are not particularly showy. The tubers, which are the main feature of the plant, are much less warty than F. capensis. The foliage consists of several twining stems, arising from the tuber, with opposite leaves which are oval, smooth and glossy compared with the crinkled leaf form of F. capensis. A considerable length of stem is produced, and one is advised to provide a larger support trellis than initially seems necessary as the foliage will outgrow almost any support provided. In England F. edulis retains its foliage and even grows during the winter when kept just frost free. A little water is required during the winter to prevent the foliage from 'self-pruning'.

Cultivation

A gritty compost with some humus is suitable. The tubers are best planted on the surface of the compost, and the vegetative growth allowed to twine around supports which should be larger than initially appears to be necessary. The foliage attracts whitefly, and periodic spraying with an insecticide or fumigation may be required to control this problem. Fockeas appreciate water and fertiliser during warm weather and this helps to swell the tubers.
 
Growth of the tubers to a showable size is faster if they are buried in the compost, which can be partly removed for showing. To increase the size of the tuber at a measurable rate, the plant should be well fed. Tubers do not seem especially prone to rotting. A minimum over-wintering temperature of 5°C is adequate providing the plants are kept fairly dry. Several species retain their leaves throughout the year, although this depends tremendously on the cultural conditions.

Vegetative propagation is difficult to impossible, and the plants are dioecious so one of each sex is needed to obtain seed. However, Fockea seed grows easily and is the best method of propagating these plants.