Echinopsis atacamensis subsp. pasacana - Columnar cactus

Echinopsis pasacana, nicknamed the candelabra cactus, is a spectacular species native to the Argentine and Bolivian Andes. Tall and slender, forming a column bristling with golden thorns and branching with age, it stands out in rocky or arid landscapes. It can be acclimatised in open ground, in a Mediterranean rockery. It also makes a striking feature on a terrace or balcony, in a large, wide pot. Hardy down to -10°C in dry soil, it is drought-resistant and requires little maintenance.

Echinopsis pasacana (syn. Trichocereus pasacana) belongs to the Cactaceae family. It originates from the Andean regions of South America, mainly in Argentina (provinces of Jujuy, Salta, Catamarca, Tucumán) and Bolivia (departments of Potosí and Tarija). It is found at altitudes between 2,000 and 4,000 metres, where it grows on the rocky, arid slopes of high mountains. The climate of its habitat is arid and semi-desert, characterised by significant temperature variations between day and night. Daytime temperatures can reach 30°C in summer, while winter nights sometimes record lows of -7°C to -10°C. Annual rainfall is low (100 to 250 mm/year) and concentrated over a few months. The air is dry, with strong sun exposure and regular winds. Echinopsis pasacana develops an extensive and deep root system, adapted to its habitat. This root network allows it to efficiently capture water in well-drained soils and anchor itself firmly in often steep and rocky terrain.
Echinopsis pasacana is a species adapted to sandy, gravelly or rocky soils, always well-drained. It tolerates extreme drought. This cactus has an upright columnar habit, with thick stems reaching 30 to 45 cm in diameter. In its natural habitat, it can exceed 10 metres in height, but its growth is very slow (5 to 10 cm per year). In cultivation, it typically reaches 1.5 to 2 metres in pots and 3 to 5 metres in open ground after several decades. Its stems have 18 to 22 well-defined ribs, covered in woolly areoles bearing long, rigid thorns, initially golden then turning greyish with age. Older specimens often branch, taking on a candelabra-like silhouette. Flowering occurs from April to July. In cultivation, flowering is triggered by a dry winter rest period at low temperatures, ideally between 7 and 10°C. The flowers of Echinopsis pasacana are large; they measure between 10 and 14 cm in length. They are pinkish-white and bloom on the sides of the stems. The floral tube is covered in long, blackish hairs. These nocturnal flowers open in the evening and remain open for 18 to 40 hours. They emit a subtle fragrance that attracts pollinators. Given its slow growth, Echinopsis pasacana only reaches flowering maturity after several decades. 
After pollination, the plant produces round fruits, measuring up to 5 centimetres in length. These fruits are dark green and densely covered in hairs. They are also edible. In South America, this cactus is pollinated by nectar-feeding bats and large nocturnal insects such as certain hawk moths. In our regions, some species may occasionally ensure pollination: night-flying moths (convolvulus hawk-moth, hummingbird hawk-moth) that visit certain nocturnal flowers or beetles attracted by the flowers' fragrance. If the plant does not produce fruit spontaneously, hand pollination is an option. Simply collect pollen from one flower with a brush and deposit it onto the pistil of another flower.

Echinopsis pasacana is an impressive plant, but its cultivation requires patience. It rewards the attentive gardener with its unique beauty and resilience. In a favourable climate, this cactus thrives in a large rockery, a gravel bed, or at the edges of a dry garden. Its bold, solitary silhouette stands out strikingly against a rocky backdrop. It can be surrounded by wispy ornamental grasses like Stipa pulcherrima, lush agaves, Hesperaloe parviflora, and other desert plants such as Dasylirions. This magnificent cactus can also be grown in a large pot on a terrace, carefully choosing the sunniest and warmest spot, which allows it to be sheltered from rain in winter.