Consulta Plantas

Care of the cactus Melocactus ernestii or Melocactus diamantinus

The genus Melocactus, family Cactaceae, comprises 40 species of cacti native to Mexico, Cuba, Central and South America. Some species are: Melocactus ernestii, Melocactus matanzanus, Melocactus intortus, Melocactus schatzlii, Melocactus peruvianus, Melocactus oreas, Melocactus deinacanthus, Melocactus curvispinus, Melocactus conoideus, Melocactus bahiensis, Melocactus azureus.

Scientific synonyms: Melocactus nitidus, Melocactus azulensis, Melocactus diamantinus. This species is native to Bahia and Minas Gerais, Brazil.

Melocactus ernestii is a cactus with a spherical or slightly cylindrical body and a dark green or yellowish colour that reaches 45 cm (17.71") in height and 35 cm (13.77") in diameter. It has 9-13 rounded ribs and areoles with 6-13 reddish radial spines (up to 15 cm/5.9" in length) and 3-8 central spines (up to 9 cm/3.54" in length). The cephalium measures up to 18 cm (7") in height and 8 cm (3.14") in diameter and has pink wool and bristles. It produces small magenta flowers. It blooms in summer.

Melocactus diamantinus is mainly used in pots for terraces and patios and as an indoor plant. In frost-free regions it is used in rockeries and in cactus gardens (tropical and subtropical climates).

Melocactus ernestii needs sunny exposure but avoiding direct sun in the central hours of the day (especially in Mediterranean climates). The safe winter temperature is 8 ºC (46.4 ºF).

The soil can be a commercial cactus substrate to which a handful of coarse sand will be added to improve drainage.

Water moderately, always waiting for the substrate to dry completely; it does not withstand prolonged drought. From mid-autumn to early spring, water at most once a month.

Fertilize every 60 days with mineral fertilizer for cacti in spring and summer.

Pruning is not necessary.

Melocactus ernestii can be attacked by red spider and scale insects if ventilation is not adequate and by fungi if there is excess humidity.

Melocactus diamantinus is propagated from seeds in a sandy seedbed sown at the end of winter at about 20 ºC (68 ºF).

Images of the cactus Melocactus ernestii or Melocactus diamantinus