Alpine Mouse-ear

Cerastium alpinum has a circumpolar arctic-alpine distribution, meaning it is found in cold mountainous and arctic regions across the Northern Hemisphere.

• Native to arctic and alpine regions of Europe, including the Alps, Pyrenees, Carpathians, and Scandinavian mountains
• Also found in arctic regions of North America, Greenland, and northern Asia
• Typically grows at elevations between 1,500 and 3,500 meters, though it can occur at lower latitudes in arctic zones
• The genus Cerastium contains approximately 200 species worldwide, with C. alpinum being one of the most cold-adapted
• Its circumpolar distribution is a legacy of glacial periods, when arctic-alpine flora was more widely connected across northern landmasses

Cerastium alpinum is a low-growing, mat-forming perennial that rarely exceeds 10–15 cm in height, an adaptation to the fierce winds and cold temperatures of its alpine habitat.

Stems & Leaves:
• Stems are slender, creeping to ascending, often forming dense cushions or mats
• Leaves are opposite, sessile, ovate to lanceolate (5–15 mm long), with entire margins
• Both leaves and stems are covered in fine, soft, glandular and non-glandular hairs, giving the plant a silvery-green to greyish appearance
• The dense pubescence serves as insulation against cold and protection from intense UV radiation at high altitudes

Flowers:
• Flowers are borne in loose cymes at the stem tips
• Each flower is approximately 10–15 mm in diameter with five white petals
• Petals are deeply bifid (split nearly to the base), giving each flower a ten-lobed appearance
• Sepals are five, shorter than the petals, with membranous margins
• Ten stamens and five styles are present
• Flowering period: June to August, depending on elevation and snowmelt timing

Fruit & Seeds:
• Fruit is a cylindrical capsule, slightly curved, opening by ten apical teeth
• Seeds are small (~1 mm), brown, and tuberculate (covered in small bumps)
• Capsule shape is the origin of the genus name 'Cerastium' (horned)

The Alpine Mouse-ear is a specialist of harsh, exposed alpine environments where few other plants can survive.

Habitat:
• Rocky alpine meadows, scree slopes, and moraines
• Crevices in limestone and siliceous rock faces
• Gravelly or sandy soils with excellent drainage
• Often found in areas with late-lying snow patches (snowbed communities)

Adaptations:
• Cushion growth form minimizes wind damage and traps warm air near the plant surface
• Dense leaf hairs reduce water loss and reflect excess UV radiation
• Low stature keeps the plant within the thin boundary layer of warmer air near the ground
• Perennial life cycle allows energy storage over multiple years, compensating for short growing seasons

Pollination:
• Flowers are pollinated by small insects including flies, bees, and butterflies
• The white, open flower structure is accessible to a wide range of generalist pollinators
• In the sparse pollinator environment of high altitudes, generalist pollination strategies are advantageous

Reproduction:
• Reproduces primarily by seed
• Some vegetative spread occurs through creeping stems that root at nodes
• Seeds are dispersed by wind and gravity, and can remain viable in the soil seed bank for extended periods

Cerastium alpinum is not currently considered globally threatened, but its specialized alpine habitat makes it vulnerable to environmental changes.

• Listed as Least Concern (LC) on the IUCN Red List at the global level
• However, local populations may be threatened by climate change, as rising temperatures push the alpine zone upward, reducing available habitat
• In some European countries, it is protected at the regional level due to its restricted alpine distribution
• Tourism, ski resort development, and trampling can damage fragile alpine meadow habitats where this species grows
• Long-term monitoring programs in the Alps have documented upward shifts in alpine plant distributions consistent with warming trends

Cerastium alpinum is a highly desirable plant for rock gardens, alpine houses, and trough gardens, where its compact form and delicate flowers can be appreciated up close.

Light:
• Requires full sun to very light shade
• In cultivation, a south-facing position with maximum light exposure is ideal
• Insufficient light causes the cushion to open up and lose its compact form

Soil:
• Must have excellent drainage — this is the single most critical factor
• Prefers gritty, sandy, or gravelly soil with low to moderate fertility
• A mix of equal parts loam, coarse sand, and fine gravel works well
• Tolerates both acidic and alkaline soils; in the wild it grows on both limestone and siliceous substrates
• Avoid rich, moisture-retentive composts which promote lush, weak growth and root rot

Watering:
• Water moderately during the active growing season (spring to early autumn)
• Allow the soil to dry slightly between waterings
• Reduce watering significantly in winter; the plant is cold-hardy but dislikes sitting in wet, cold soil
• In alpine house cultivation, ensure good ventilation to prevent fungal issues

Temperature:
• Extremely cold-hardy, tolerating temperatures well below -20°C when properly established
• Requires a period of winter cold dormancy
• Does not tolerate hot, humid summer conditions — struggles in lowland gardens with warm, wet summers
• Best suited to cool-temperate and subarctic climates

Propagation:
• By seed: sow fresh seed in autumn and expose to natural cold stratification over winter; germination occurs in spring
• By division: carefully divide established cushions in early spring
• By cuttings: take small stem cuttings in late spring and root in gritty, well-drained medium under light shade

Common Problems:
• Crown rot from poor drainage or winter wet
• Leggy, open growth from insufficient light
• Failure to thrive in warm, humid lowland conditions
• Aphid attacks on new growth in spring