Irish Moss ( Sagina ) Seed

Irish Moss (Sagina subulata) is a beautiful, low-growing evergreen perennial that forms dense, velvety carpets of emerald-green foliage accented by tiny, star-shaped white flowers in late spring and early summer. Despite its common name, Irish Moss is not a true moss but a hardy flowering plant that creates the same lush, moss-like appearance. It is one of the finest ground covers for filling spaces between stepping stones, edging pathways, softening rock gardens, and creating miniature garden landscapes.

Garden Uses

Irish Moss is ideal for rock gardens, alpine gardens, fairy gardens, miniature landscapes, borders, edging, pathways, and planting between stepping stones or pavers. Its dense, cushion-like foliage creates a beautiful living carpet that contrasts wonderfully with larger perennials, ornamental grasses, dwarf conifers, and natural stone. It also performs exceptionally well in trough gardens, containers, and as an attractive lawn substitute in lightly trafficked areas.

Growing Information

Sow seeds indoors 8 to 10 weeks before the last spring frost or sow outdoors after danger of frost has passed. Scatter seeds over the surface of a moist seed-starting mix and press them gently into the soil without covering deeply, as light aids germination. Maintain temperatures between 60° and 70°F while keeping the growing medium evenly moist. Germination usually occurs within 14 to 21 days.

Transplant seedlings into full sun in cooler climates or partial afternoon shade in warmer regions. Irish Moss prefers fertile, well-drained soil with consistent moisture but does not tolerate standing water. Once established, plants spread gradually into soft, dense mats. Occasional trimming after flowering helps maintain a neat appearance and encourages fresh growth.

Seedman Notes

Irish Moss is one of our favorite living ground covers for adding elegance to rock gardens and pathways. Its rich green foliage remains attractive nearly year-round, while the delicate white flowers add a touch of sparkle each spring. Whether planted between stepping stones, cascading over rocks, or filling miniature landscapes, it creates a timeless, natural appearance that only improves with age.

Quick Facts

Important Note: These are very tiny seeds, even smaller than tobacco or petunia seeds. They are easily germinated by following instructions above, but they must be started inside and transplanted outside as "plugs". These will not germinate well outside, except in some instances where they are sowed between flagstones.