The genus does not include many species, but it is not always easy to recognize the exact one if you do not analyze the plant closely. Several of them are grown as indoor ornamental plants. Spines are arranged around the leaves as a defense against herbivores. The development of these plants is columnar, they grow aiming high with a scarce lateral development. Plants in cultivation can, but rarely, flower with the tiny flowers in open thyrses at the tips of the branches being interesting, but not particularly attractive. Alluaudias are dioecious, so male and female plants need to be grown for them to fruit.
The genus is named after Charles Alluaud, French entomologist who also collected plants.
Growing Conditions and General Care
Alluaudias need full sun or high interior lighting with a very well drained soil mix and freely circulating air. The best way to water these succulents is to completely soak the soil and then let it dry out completely before you water again. If fertilizer is used, it should be diluted to 1/4 the recommended rate on the label.
These plants must be protected in the greenhouse over the winter. Established Alluaudias should tolerate temperatures around 32 °F (0 °C). During the winter months, the plants will drop all of their leaves and no water should be given during this period.
If planted in the landscape, however, it will often drop all its leaves when it decides to take a rest. When this happens, cut down on the watering until the leaves start to appear again.
Alluaudias are propagated from cuttings taken in the spring or from seed when available.