Mammillaria ernestii


Mammillaria fertilis
Chilita fertilis
Neomammillaria fertilis
Mammillaria isotensis
Mammillaria backebergiana subsp. ernestii


The name “Mammillaria ernestii” is actually a synonym for “Mammillaria backebergiana subs. ernestii”. The latter is native to Mexico, where it’s widespread in Guerrero, Michoacan, and Mexico. This species grow on very steep cliffs, where it kind of clings on them. Precisely for its inaccessible habitat, very little is known about this plant, apart from the fact that it grows associated to other succulents such Agave brevifolia and Selaginella lepidophylla.


Mammillaria backebergiana is a tiny cacti that, in time, becomes coloumnar, with stems however not taller than 30 centimeters and very slender: 5-6 centimeters in diameters, so that they may grow crooked or may start to fall a little bit, if they are not equipped with a support. Like every Mammillaria, M. backebergiana is equipped with a lot of nipple-shaped tubercles. The name “Mammillaria”, in fact, refers precisely to the tubercles of its stems, that look like nipples. In this species, in particular, tubercles are slightly tetrahedrical, with their axils that can be bare or covered by a few bristles. On the tubercles, 8 to 12 yellow but brown-tipped radial spines grow, along with 1 to 3 central ones, 8 millimeter long, also yellowish-brown. Spines can be so dense that they give the impression of a yellowish hair. The subspecies we are describing, M. ernestii or either Mammillaria backebergiana subs. ernestii, is not so different than the regular form, but it has a stem coloured in a darker green and a central spine (instead of three of them) which is usually, also, darker. The two forms also share the flowers, which are purplish red and grow solitary at the top of the stems, forming the typical “blooming crown” of the Mammillarias.


M. ernestii is not so difficult to grow. Here below are our cultivation tips:

If you choose to put it indoors, choose a spot exposed to direct sunlight. If, instead, you choose to place it outside, provide it with filtered light and some shade: remember that, in its natural habitat, it grows under other bushes.
M. decipient is a resistant species: it can drop to -5ºC if its substrate is maintained dry. By the way, to stay safe, we advice to put it indoors during the cold season or, at least, to shelter it, especially providing protection frmo Winter rains. Also, it requires strong light and low air humidity in Winter; a good idea could be to place it exposed to air drafts.
Water moderately from spring to autumn and regularly in summer. Also during the hottest period of the year, however, wait always for the soil to dry up completely before each watering, as this plant is subsceptible to rot. During the winter temporarily suspend the watering, preserving the plant from excessive moisture.
Mammillaria ernestii requires a standard soil for cacti. Any substrate you choose, anyway, should be very well-drained.
During the growing season, fertilize once with a product specific for cacti, rich in potassium and phosphorus but poor in nitrogen.
Repot every year at the end of the vegetative period to support growth that is very fast and vigorous. 


Propagation can be carried out either through sowing and cuttings. Seeds must be placed on the surface of a sandy and humid soil at about 20 ° C. Some species produce lateral suckers that can be cut and used as good cuttings. It is the case of M. decipiens it will form dense clumps in a very few years and it can be propagated very easily through cuttings. When your M. decipiens gets old and you see it’s sufficiently clustered, you can start to take off cuttings in spring and summer by cutting off the stem with a sharp knife. Put the cut branch in a warm place for around a week to let the wound dry up and then plant it in a pot filled with some cactus potting mix. It’s important to create a superficial layer of coarse grit and to lie the cutting on it: it prevents the wound to become too wet. If you choose sowing as a method of propagation, remember that seeds usually germinate in 8-13 days at temperatures of 21-27ºC. They should be placed in a light substrate and maintained slightly moist and covered with a glass until they germinate.


The name “Mammillaria” refers precisely to the tubercles of its stems, that look like nipples. The name “Mammillaria ernestii”, instead, is actually a synonym for “Mammillaria backebergiana subs. ernestii”.

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