Silene acaulis

Silene acaulis, also known as Silene acaule or Alpine cushion, is a small, stemless, robust perennial that grows on limestone and rocky soils up to an altitude of 3700m (12139ft)! It forms mossy cushions that bloom with pink flowers in summer. The pleasantly fragrant flowers, emerge from a very low and dense cushion of small, bright green leaves. Combining strength and delicacy, this low-maintenance plant is perfect for mountain gardens, alpine rockeries, sunny borders, and poor, well-drained soil.

Silene acaulis belongs to the Caryophyllaceae family, like carnations. This botanical species is found in subarctic regions of Asia, North America, and Europe, common in the northern and southern Alps. It grows in rock crevices, scree, and short grass meadows, preferring limestone sites. This perennial is quite slow growing and its mature size will not exceed 5 cm (2in) high and 35-45 cm (14-18in) wide. Contrary to what its species name suggests (acaule means stemless), this Silene develops a small stem.
Silene acaulis forms a small cushion-shaped tuft. Its narrow, linear, pointed leaves are 1 cm (0in) long and 2 mm (0in) wide, leathery and bright green. This colour enhances the flowering, which takes place from June to August depending on the climate. Slender, purplish stems emerge from the foliage and bear beautiful solitary flowers with 5 candy-pink, notched petals with a swollen calyx, often tinged with red. The 20 to 25 mm (1in) wide flowers, are rich in nectar and attract bees. A powerful taproot firmly anchors the plant to the substrate and makes it resistant to strong winds. The centre of the cushion often appears brown, due to the presence of dead leaves that can accumulate there. Some specimens in European mountains measure 50 cm (20in) wide and are estimated to be 100 years old.

Silene acaulis is a plant of slopes and rocky areas, resistant to cold, tolerant to drought, and disliking heatwaves. As a pioneer species in disturbed terrain, it can be accompanied by other flowering cushions such as helianthemums, dwarf artemisia (Artemisia lanata), wall bellflower (Campanula muralis), Caucasian rock-cress (Arabis caucasica), moss phlox (Phlox subulata), ice plant (Delosperma cooperi), trailing daisy (Erigeron karvinskianus), and bloody cranesbill (Geranium sanguineum). This plant forms a beautiful clump between the stones of a wall or pavement...