Puya alpestris

The Puya alpestris, sometimes known as the Sapphire Tower, is a perennial native to the Chilean Andes that will delight botanical enthusiasts. Less well-known than its parent, the yellow-flowered Puya chilensis, it is also less impressive than its cousin, the Puya berteroniana, but it flowers at a younger age and in an equally unreal range of colours. This Chilean cousin of pineapples first forms a rosette of long, slender, toothed leaves, green-gray in colour, and then a highly original branched floral spike adorned with dark green-blue flowers with metallic reflections and punctuated with orange stamens. They are filled with nectar that Chilean birds love. This flowering often marks the death of the rosette that bears it, but the plant ensures its survival through daughter rosettes and spontaneous seedlings that germinate under favourable conditions. Still rare, this puya is increasingly attracting exotic plant enthusiasts who care for it in pots and is starting to appear in our gardens in mild climates.

The Puya alpestris is a succulent perennial plant belonging to the bromeliad family. It is native to the foothills of the Andes, at the latitude of Santiago de Chile, within a vegetation cover reminiscent of our scrubland and maquis. It can be found anchored in rocky cliffs or somewhat arid heathlands, on poor, leached soils, often basaltic, dry in winter and summer. This high-altitude botanical species tolerates short frosts of around -6°C (21.2°F) in very well-drained soil. It is cultivated somewhat like a cactus and its foliage persists throughout the year.

The plant grows quite slowly, forming a rosette of basal leaves that spread in width by producing shoots late in its life. The leaves, which can measure up to 70 cm (28in) in length, form a fountain-like clump that eventually reaches 80 cm (32in) to 1 m (3ft) in all directions. They are curved towards the ground, very narrow, leathery, pointed, covered with a waxy film, and lined with fine, hook-shaped, formidable teeth. Their colour, greener in winter, takes on silvery reflections in summer due to heat and drought. Flowering usually takes place in late spring in our latitudes, in May-June. From the centre of the mature rosette, a 1 m (3ft) or 1.20 m (4ft) tall almond green floral spike covered with flower buds emerges. The first flowers open on the main stem, which then branches into sterile secondary stems on which birds perch. The flowers, with their three fleshy, shiny petals, green-blue turquoise with an iris-like appearance, form deep cups. They are numerous and densely packed together. Each flower measures 3 to 4 cm (1 to 2in) in diameter and has three stamens covered in orange pollen. They are filled with a syrupy blue nectar that birds and large pollinating insects relish. The Puya alpestris most often survises through the development of daughter rosettes that emerge near the stump before flowering.

This Puya alpestris is a collectible plant that deserves a prominent place in our gardens in mild climates. It can be placed in a large exotic rockery, for example alongside Yucca, Dasylirions, or modest palm trees, Phormium, or hardy tall candle cacti such as Echinopsis, Cereus strausii, or aethiops. This plant can be easily cultivated on a terrace, in a cactus soil mix, where it will thrive in a large pot. As soon as the first cold weather arrives, you should store it, handling it with care as this puya is very "clingy," in a greenhouse or conservatory. Undoubtedly one of the most unique Puya species, it is definitely worth trying to cultivate it in the ground in our mild regions.