Melocactus azureus 5.5cm
Origin and Habitat: Central and northern Bahia, eastern Brazil.
Altitude: 450-800 meters above sea level.
Habitat: This species has a small range and is restricted to low-lying outcrops of limestone. The species occurs in subpopulations of a few hundred individuals, however, in some there are millions. Habitat loss for agriculture is a major threat, the vegetation gets destroyed when the surrounding caatinga forest is cleared for cultivation causing a continuing decline of the natural populations. Also, the change in the surrounding vegetation has an impact on the outcrops were the species grows, making them prone to invasive species.
Description: It is one of most desirable of the Brazilian melocactus because of its striking frosty blue epidermis.
Growth rate: It is a relatively rapidly growing given the best conditions.
Soils: It likes very porous standard cactus mix soil.
Repotting: The root system is weak and generally resents being re-potted and can take a long time to re-establish. Use pot with good drainage.
Light: They prefer very bright light, not as much as the most arid growing cacti, but plenty nonetheless. Tends to bronze in strong light, which encourages flowering and heavy spine production.
Watering: Melocactus grow from April to October and cannot endure long stretches of total dryness and also too much water will rot them, as their weak root systems tends to be inefficient at sucking up water from wet soil. Nonetheless, again as a result of their tropical origins, they need a fair amount of water, but allow the soil to dry quite a bit before watering again.
Fertilization: Feeding may not be necessary at all if the compost is fresh then, feed in summer only if the plant hasn't been re-potted recently. Do not feed the plants from September onward as this can cause lush growth which can be fatal during the darker cold months.
Hardiness: Melocactus rest from October to April but can’t stand cold, or even fairly cool temperatures, so is indispensable to keep them above 8-12°C at all times, severe damage or death occurring at temperatures that the great majority of cacti wouldn’t mind in the least and prefer more frequent water in winter than other cacti, say once a month. (but hardy to 4 C ° C for short periods). However warmth throughout the year will increase the growing success (minimum 12° to 20° C during rest season). In the rest period no high atmospheric humidity.