Oreocereus trollii - Old man of the Andes

On the arid heights of the Andes stands Oreocereus trollii, the Old Man of the Andes, draped in its cloak of white wool, compacted into short, thick columns. Beneath this venerable fleece lurk formidable reddish prickles, testaments to its wild character. In full sun, in perfectly drained soil and under a dry climate, it will easily withstand frosts down to -12°C. Whether in a pot on a balcony or at the heart of a Mediterranean rockery, its singular personality never fails to make an impression.

Oreocereus trollii, nicknamed the Old Man of the Andes, is a columnar cactus belonging to the Cactaceae family. Native to the mountainous regions of northern Argentina (provinces of Jujuy and Salta) and southern Bolivia (departments of Chuquisaca, Tarija, and Potosí), it thrives at altitudes between 2,900 and 4,300 m. This species was first described in 1929 by Walter Kupper under the name Cereus trollii, before being reclassified in 1936 by Curt Backeberg into the genus Oreocereus. The name Oreocereus trollii pays homage to the German botanist Wilhelm Troll. This cactus exhibits slow growth and develops columnar stems branched at the base, forming small clumps. The stems, initially almost spherical, become cylindrical over time, reaching 50 cm in height in cultivation, though in their natural habitat, they can grow up to 1 m. Their diameter ranges from 6 to 10 cm. The stems feature 15 to 25 tuberculate ribs, adorned with white areoles from which fine white woolly hairs, up to 7 cm long, emerge, protecting the plant from the extreme climatic conditions of its environment. The 3 to 5 central thorns are robust and measure up to 5 cm long. They display yellow, reddish, or brown hues with darker tips. The 10 to 15 radial thorns are finer and resemble hairs. The flowers appear between June and August, depending on the climate, on mature specimens. They are semi-tubular, pink to carmine red, and measure up to 4 cm long. Pollination is typically carried out by insects outdoors. The fruits are spherical, dry, and split when ripe to release black seeds.
To encourage flowering, it is essential that this cactus receives maximum sun exposure. Additionally, a cool, dry winter rest period is highly beneficial.

In a sun-drenched gravel garden, the Old Man of the Andes stands as a living sculpture. Its woolly silhouette contrasts starkly with raw stone and fleeting twilight shadows. Its columnar form pairs perfectly with the blue-tinged cushions of Senecio mandraliscae. Agave parrasana, with its compact cabbage-like rosettes, will sculpt the space around these two companions. In a pot on a sun-drenched terrace, lay a bed of light gravel to reflect the light and accentuate the softness of its fleece. Placed among terracotta or turquoise ceramics, it evokes the Andean landscapes.