How to Garden Irish Moss

Irish moss (sagina subulata), a perennial plant and not a true moss at all, hardily survives freezing temperatures. In summer, it produces small white flowers, adding a nice touch to rock gardens, walkways, and walls where it has been planted. Irish moss is commonly gardened by seed. Although bedding plants are available at nurseries, seeding is much less expensive for large plantings. Irish moss requires minimal care and will thrive and survive light foot traffic when planted between pavers or stones.

Difficulty: Easy

Instructions

Things You'll Need:

• Hand cultivator
• Mist attachment
• Fertilizer

1. Plant Irish moss in sandy, well-drained soil, where it will receive partial shade. Preferably, it should have shade in the afternoon and sun in the morning. Loosen soil between stones or rocks with a hand cultivator before seeding.

2. Sow seeds four inches apart for clumping varieties and eight inches apart for spreading varieties of Irish moss. Sow directly on the soil surface, then cover with a 1/8" layer of soil.

3. Water after sowing, using a mist attachment on the hose. Water daily as necessary to keep the soil moist at all times but not soggy. Germination should occur in 14 to 21 days.

4. Use a general fertilizer after the moss blooms in summer, following label recommendations for application amount. Fertilize in spring starting in the second year, when the plants begin growing actively.

5. Keep the soil moist at all times. Irish moss goes dormant in the fall, and additional water isn't necessary until spring.

Tips & Warnings

• Sow Irish moss in autumn after the temperatures have cooled or in spring once temperatures reach 50 F.
• Shade Irish moss beds during hot, dry periods with lattices or other structures to avoid damage to the plants.
• Irish moss may turn brown during hot weather, but if properly watered, it will turn green again when the weather cools.
• Slugs will damage Irish moss. Treat slug problems immediately with chemical or organic controls.

References

• Washington State University Extension
• Ohio State University