INVASIVE ALIEN SPECIES - Queen of the night: Part 1

With no natural enemies in Southern Africa, this cactus can invade the veld with impunity. The law requires that it be controlled in gardens and on farms.

Queen of the night (Cereus jamacaru), also called the Peruvian apple cactus, is a large, upright-growing, cylindrical cactus species endemic to South America. Because of its attractive shape, large, white flowers and edible fruit, it is a popular ornamental plant in many South African gardens, from where it may spread into the surrounding veld, threatening the natural vegetation.

C. jamacaru is a perennial succulent tree that reaches between 6m and 7m in height. It usually consists of a short main stem from which numerous thick, vertical branches grow. Sometimes, however, it occurs as a multi-stemmed shrub.

The stems are succulent, green, spiny, and covered with a bluish waxy layer. The stems have four to nine (usually six) conspicuous lateral ribs on which spines occur in groups of six to eight. The spines are 10mm to 20mm long, sharp, straight, and dark coloured.

Each group of spines grows on a brown or grey protuberance (areole) arranged 10mm to 25mm apart on the ribs. The stems are indented at irregular distances, creating the impression of segments. The very young growth tips have succulent leaves on the ribs, but these soon drop off, so that the plant can be regarded as leafless.

The lateral branches arise from the dormant axillary buds between the spines.