Family: Cactaceae
Habitat: High altitude desertic environments with very severe temperature ranges, in California, Utah, Colorado, New Mexico (USA).
Cultivation: Full exposure to sunlight, well-draining substrate, careful with watering.
Curiosity: Already from the name, “Sclerocactus”, which in Greek means “hard cactus”, you can see how tough these plants are!

KEY FEATURES

Sclerocactus is a genus of perennial plants belonging to the family Cactaceae. Already from the name, “Sclerocactus”, which in Greek means “hard cactus”, you can see how tough these plants are! Their natural habitats are in fact high altitude desertic environments with very severe temperature ranges: Sclerocactus can withstand both very high and very low temperatures.

Those extreme habitats are found mainly in California, Utah, Colorado, and New Mexico in the United States.

Sclerocactus tend to be cylindrical or globular plants, of variable height depending on the species, with 12-20 evident ribs or, in some cases, tubercles, on the ridges of which are placed the areoles from which many thorns branch off, which are so long and numerous that they form such an intricate structure that the green stem becomes almost inaccessible without wounding the hands. In some species, some of the thorns are also hooked.

This thorny structure, according to some authors, is itself an attempt to adapt to the extreme conditions in which these plants live. According to these authors, their thorns would be used to ensure that, during the rare storms of the desert, the plant gets stuck in the debris and mud carried by the water, to be uprooted and ” transported ” to points where the water accumulates, where therefore it is more likely the, at least sporadic, presence of water. However, it is not a verified theory: in its favor, however, goes the fact that the stems often have lacerations, probably brought by debris. The seeds of this plant germinate in areas subject to water runoff (i.e. on slopes, where rainwater falls), or in water storage points.

Sclerocactus flowers are large and flashy: they usually bloom in groups of 3-4 large flowers on the top of the plant and can take on various colors: red, yellow, purple, white, pink, etc… These wonderful flowers are one of the reasons why succulent lovers go crazy for them!

VARIETY AND TYPES

Here below are some species of Sclerocactus:

• Sclerocactus spinosior
• Sclerocactus uncinatus

TIPS FOR GROWING

Sclerocactus are not so difficult to grow. However, it is important to provide them with a well ventilated room or put them outside in a sunny position. Also because, as houseplants, they can give some problems because of their bristling thorns! However, it would be good to shelter them from rain during winter. The greenhouse, however, is not good, as it is a poorly ventilated environment. At the end of the summer you can observe your Sclerocactus “deflate” in preparation for winter dormancy: the plant expels water and thus greatly reduces its size. You won’t have to water them during the cold season. These plants require very low temperatures to enter a state of dormancy so that they can flower in Spring. As a substrate, it is advisable to choose a sandy, well-drained substrate with a good mineral component.

Sclerocactus propagation, in theory, should be done by sowing. In practice, however, the chances of success are very low, because the seed should be scarified at low temperatures to get out of dormancy and germinate. That’s why Sclerocactus are often grafted either on other Sclerocactus or even on other species, including Opuntia.