Alluaudia humbertii is an endemic species of Madagascar, listed in the II Appendix of CITES, which leaves in arid regions, usually over acid soils and red sands.
Alluaudia humbertii is a tropical perennial plant, endemic of Madagascar. It can assume the form either of a shrub or of a tree with a maximum height of 5-7 meters. It is distinguishable from the more common Alluaudia procera for its smaller stems. The diameter of Alluaudia procera’s stems, indeed, is the double of the one of Alluaudia humbertii’s stems. The plant has a really short trunk, so that branching starts really close to the ground so that the branches formed are really long and tend to arch in a very pretty way, at least in young individuals. In mature plants branches are erect and make the plant taller. Leaves are small, lined on the branches, fleshy, obovate, bright green. They are arranged in pairs and, at the axil of each pair of leaves there is a pair of spines. Flowers are small (their maximum diameter is 1 centimeter), and they bloom, in our Northern hemisphere, from August to October.
Alluaudia humbertii’s natural habitat is severely dry and arid. To cultivate this plant, you’ll need a cactus, sandy mix, really well-drained. Water it seldom, but remember that this rare watering must be abundant, because the plant is very capable to store water in its tissues. Wait until the soil is completely dry before each watering. This plant need high temperatures which should never descend below 10ºC. Alluaudia species’ growth is very rapid, so repotting is necessary at least every two-three years.
Propagation can be made by cuttings, taken off usually in Autumn or in Spring, or by seeds.
The Allaudia genus counts in all six species, all coming from Madagascar. It is a plant that has not had spontaneous spreading in environments different from its own.