This genus includes only two species of cacti originating in Mexico. They have a very slow growth and over the years the specimens can reach the 15-20 cm of diameter, producing also many lateral shoots; they have a globular body, of grey-green colour, with 9-11 ribs, of which the most pronounced ones have small areoles with white thorns which detach with the passing of the years. In summer, they produce white or pink tubular flowers, usually in the apical zone.
These cacti are not very common because the cultivation is quite difficult and the growth is very slow.
The aztekium love semi-shady positions and fear too many hours of direct sunlight; in winter they can bear short frosts if kept completely dry, to have a well-developed plant it is best to grow it in places with minimum temperatures around 10°C.
During the growing season, from March to October, water regularly, with small amounts of water and waiting for the soil to dry completely between one watering and the other. With the arrival of the cold, drastically reduce watering, to allow the plant to begin its vegetative rest. In spring and summer provide fertiliser for succulent plants every 20-25 days, mixed with water from the watering.
They need very well drained soils, mainly composed of sand and fine pumice or volcanic lapillus. It is not necessary to repot too often these plants that develop a fleshy root.
Generally, these plants propagate by removing the shoots from the mother plant and rooting them in individual containers. If desired, small black seeds can also be sown, even if they are not always fertile.
Aztekium: Parasites and diseases
Cultivating aztekiums in poorly drained soil can promote the onset of root rot, which can quickly compromise the entire plant; excessive watering and poor air circulation can lead to uncontrolled development of cochineal.