Irish Moss

Irish Moss (Sagina subulata)

Irish Moss is a very low, moss-like groundcover that forms dense, emerald mats dotted with tiny white star flowers in late spring to early summer. Its fine texture fills gaps between stones and softens path edges in cool, moist, well drained sites.

Distinctive Features

Finely tufted foliage creates a carpeted look with delicate blooms that brighten shady pockets. Tight, cushiony growth provides a seamless finish at the front of borders and along flagstones.

Growing Conditions

• Sun Exposure: Full sun to partial shade; afternoon shade is helpful in hot summers.
• Soil: Moist, well drained, humus-rich soil that stays cool; avoid soggy or compacted sites.
• Water: Keep evenly moist, especially during heat and establishment; do not allow to dry out.
• USDA Hardiness Zones: 4 to 8.
• Mature Size: About 0.5 to 1 in tall and 1 to 2 ft wide as a spreading mat.

Ideal Uses

• Focal Point: Luminous green carpet with starry flowers draws the eye in small spaces.
• Between Stepping Stones: Cushions joints with limited, careful foot traffic.
• Edging: Creates a neat living border for paths and rockwork.
• Rock Gardens: Tucks into crevices where soil stays cool and moist.
• Container Topdressing: Forms a soft living mulch around specimen plants.

Low Maintenance Care

• Watering: Maintain consistent moisture; increase frequency during heat or wind.
• Pruning: Shear lightly after bloom to refresh and tighten the mat.
• Fertilizing: Feed sparingly in spring with a diluted balanced fertilizer.
• Mulching: Apply a thin, fine mulch to conserve moisture without burying crowns.
• Notes: Not drought tolerant; protect from intense afternoon sun and from winter waterlogging.

Why Choose Irish Moss?

• Seamless Finish: Forms a uniform, moss-like carpet in cool, moist sites.
• Delicate Bloom: Tiny white flowers add seasonal sparkle.
• Refined Texture: Fine foliage contrasts with stones and larger leaves.
• Space Efficient: Ultra-low habit fits tight gaps and edges.
• Design Versatility: Works in rock gardens, paths, containers, and small courtyard beds.

Provide cool exposure with reliable moisture and sharp drainage, and lightly shear after flowering to maintain a dense, vibrant green carpet.