Perennial of the Caryophyllaceae family, native to the mountains of western North America, from the Rockies to the Sierra Nevada. It occupies alpine lawns, scree, and rock crevices at high altitudes, on well-drained substrates, often between 2,500 and 4,000 meters.
It forms a dense and spreading cushion, rather flat than domed, only 3 to 5 cm in height, but can cover an appreciable area over time. The leaves are short, spatulate to slightly obtuse at their tip, which gives it its epithet, of a fresh and deep green, arranged in tight tufts that give the plant a texture reminiscent of coarse moss. This dense and regular foliage remains the main asset of the plant, even outside of flowering.
The flowers are small, white, with five petals, borne individually on short peduncles, discreetly scattered over the cushion without overwhelming it. In its natural habitat, flowering extends from July to August.
It requires full sun, a very well-drained, mineral and poor soil, preferably slightly acidic. It tolerates intense cold well but dreads stagnant moisture in winter. A trough or elevated rockery suits it better than ordinary garden soil.