Accessorised in eye popping pink and with all the lissom grace of a super model, a mature Arrojadoa pencillata is a sight to behold. Even for a hardened succulent grower like me, this one is at the top of the list of plants that I would hate to lose to that great desert in the sky.
Named in honour of the botanical collector Dr. Miguel Arrojado Lisboa, who was superintendent of the Brazilian Railways at the time that Britton and Rose described the genus in 1922, Arrojadoa is a genus of shrubby, clump forming ceroid cacti found in Brazil on the plateaux south of the Amazon River. As with other members of the genus, Arrojadoa pencillata grows under or through shrubs in the desert scrubland known as the caatinga, where the temperature stays at a fairly constant 25°C throughout the year.
Fig. 1 Arrojadoa pencillata showing new growth through the cephalia
In the greenhouse it is happy in a standard, well-drained soil mix with a generous weekly water when in growth and the odd feed with a low nitrogen fertilizer. In the winter, it needs to be kept dry at a minimum of 10°C and, as my plant is now too tall to fit on the hotbed bench, it has to sit on the floor where it gets the prime spot right next to the gas heater.
Fig. 2 A mature Arrojadoa pencillata
For the first few years young plants form rather underwhelming slender stems of 1-2cm across, but when mature the branches at the end of the growing season terminate in a felted cephalium surrounded by a ring of longer bristles. Throughout the summer this formation produces slender, fleshy flowers in a stunning Day-Glo pink. The following spring, the branches grow through the cephalium stretching out to form a new cephalium for the next season’s flowers. The plant is something of a martyr to mealbugs, with a horrible tendency to suffer stealth infestation of the cephalia so keep your bug gun to hand!
Fig. 3 Arrojadoa pencillata showing detail of the flowers and cephalia
Cuttings can be taken by breaking off new stems at the cephalium. The plant is not permanently disfigured as a new stem will grow the next growing season and the cuttings, with a little persuasion from a hotbed, will slowly root to form new plants.
Gillian Evison
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