Irish Moss (Sagina subulata): Emerald Moss-Like Carpet for Cool, Moist Sites

Irish moss, also called pearlwort, is a tiny, mat-forming perennial that creates a dense, moss-like carpet of emerald-green foliage. It is not a true moss but a flowering plant, perfect for filling gaps in cool, moist, shady areas.

Botanical Profile

• Family: Caryophyllaceae
• Genus: Sagina
• Species: subulata

Features

Forms a prostrate mat ½–1 inch tall. Leaves are awl-shaped, bright green, densely packed. Tiny white flowers on thread-like stems in late spring. Evergreen in mild climates.

Culture

Part to full shade. Consistently moist, rich, well-drained, acidic soil. Cool summers preferred. Hardy in USDA zones 4–8. Intolerant of heat, drought, and foot traffic. Divide in spring to propagate.

Uses

Between stepping stones, rock gardens, troughs, fairy gardens, Japanese gardens. Not a lawn substitute.