Ornamental plant enthusiasts appreciate thorn cactus for their distinctive appearance. The spines on this cactus are an adaptation to their native dry and hot conditions and are a modified form of the leaves. The functions of the thorns include reducing evaporation, catching morning dew, and protecting the plant from predators. Thorn cactus also have thick, wax-coated stems to store water reserves, allowing them to survive for long periods without watering.

In Indonesia, various types of prickly cactus such as mammillaria, ferocactus, and gymnocalycium are sold, typically imported in seed form and cultivated. The cactus typically reaches 5-8 cm in diameter within a year of sowing.

Mammillaria cactus has a spherical shape with thorn-covered tubercles and is one of the largest genera of the cactus family, consisting of approximately 200 species. Some popular species include Mammillaria gracilis, M. prolifera, M. elongata, and M. mammillaris. Most of the mammillaria species originate from Mexico, with the genus name referring to the nipple-like projections characteristic of the cactus in this genus.

Ferocactus resembles a starfruit and typically has 13-22 ribs. It is a genus of large barrel-shaped cactus with large spines and small flowers. There are approximately 30 species of ferocactus, primarily found in the southwestern United States and northwestern Mexico.

Gymnocalycium cactus has slightly rounded ribs and is found in South America. There are reportedly around 70 identified species within this genus. The name Gymnocalycium means bare and refers to the plant’s flower buds, which have no spines or thorns. Popular species within this genus include Gymnocalyciumbaldianum, G. mihanovichii, G. eurypleurum, and G. bruchii.

Cactus of the genera mammillaria, ferocactus, and gymnocalycium are grown either independently or grafted onto hylocereus, cereus, and pereskia rootstocks to stimulate their growth.