My plant was small, barely trunking and incredibly nondescript when it arrived about 5 years ago. Since then it has surprised me with a deceptively steady growth rate, developing a half-metre trunk and putting out this rather matte lizard-green rosette that extends around 80cm in diameter and trimmed with these bijoux russet spines. They're usually pretty innocuous but can certainly open up some skin if you yank your hand back the wrong way.
The leaves are pliant and remain green all year round with the exception of spring, when the lower half start to crisp and brown at the ends, presumably as stored energy is expended in expansion and flowering. Labouring under the assumption that it was some sort of dreadful pathology, I tried a number of tactics to curb this seasonal browning before coming to the conclusion that it’s just one of rupicola’s cyclic quirks. The dead leaves form a papery skirt that I leave in place just in case it helps protect against temp drops in winter.
While my rupicola enjoys a dry winter under cover, it is totally exposed to our Zone 9 winter temps which went as low as -2 ºC this year for a few days in a row. This plant wasn’t directly frosted under plastic sheeting but it was a bloody cold few days for our coastal New Zealand microclimate and this didn’t affect even the tender emergent flower stalk. I’ve actually never seen it adversely affected by cold and would rate its hardiness as comparable to Aloe speciosa, which I grow in the ground here, at least in a well-drained position.
Aloe rupicola is an odd plant, quite unlike any other in my fairly extensive collection and certainly the most dainty and singular of my tree aloes. Which is in stark contrast to its notable hardiness and vigour. Aloe rupicola misrepresents itself with the sinuous delicacy of its vaguely pinstriped leaves and slender stature; in the wild it inhabits what appears to be crappy humus pockets in a nasty old high-altitude boulder-strewn patch of Chimbango Hill in the Bié district of Angola.
Not exactly luxury living.
My overall impressions of Aloe rupicola are moderate size, attractive foliage, decent growth rate, cold-hardiness, undemanding cultivation (mine's in a shitty plastic pot with proprietary cactus mix) and ready flowering. It doesn't seem to suffer any of the spotty fungal leaf pathologies that afflict a number of other aloes in this humid coastal situation, which is an important bonus. The one thing it does not seem to appreciate is massive amounts of harshest midday sunlight, presumably because it has evolved as a semi-understorey species in open hill scrub in its native clime; mine is happiest in half day shade and/or filtered sunlight, perhaps even looking its best in these conditions.
A recommended species for those with neither the room nor the climate to accommodate the larger tree aloes and one that would look particular striking and serpentine planted in groups.