Silene acaulis

Perennial of the Caryophyllaceae family, circumpolar arctic-alpine, present in all major mountain ranges of Europe — Alps, Pyrenees, Apennines, Carpathians, Scandinavian mountains — as well as in Iceland, Greenland, and the Arctic regions of North America. It is one of the most widespread cushion plants of the high mountains.

It colonizes alpine and subnival lawns, windy ridges, stabilized scree, and sunny rocks, generally between 1,800 and 3,500 meters, indifferent to calcareous or siliceous substrate provided the drainage is perfect. It withstands prolonged snow cover and a very short growing season.

The plant forms dense, tight, and persistent cushions, bright green, reaching several tens of centimeters in diameter for only 2 to 4 cm in height. The leaves are tiny, linear, ciliate on the edges, imbricated in rosettes that constitute the compact framework of the cushion. The flowers, solitary and sessile, are placed directly on the surface of the cushion without an apparent peduncle, with five bright pink to pink-lilac petals, sometimes almost white depending on the individuals, with a well-visible reddish to purple tubular calyx.

In its natural habitat, its flowering extends from June to August depending on altitude and exposure. In cultivation, it blooms in May-June.

An aged cushion can represent several decades of slow growth, the plant progressing only a few millimeters per year. This extremely measured pace is one of the most remarkable adaptations of the species to the harshness of the alpine environment.

In cultivation, it requires absolute drainage, a lean and mineral soil, and full light. It dreads stagnant moisture in winter and excessive heat in summer. It is cultivated in alpine troughs, rock crevices, or well-exposed rock gardens, and is more accommodating in a cool Atlantic climate than in a hot continental climate.