Irish moss (Sagina subulata) is a low-maintenance groundover that is perfect for use in rock gardens, between pavers, at the edges of a path and as a low-footfall, limited area lawn substitute. This lush and low-growing evergreen perennial resembles moss, but it is part of the carnation family (Caryophyllaceae) and has much different growing requirements than moss. This is a very hardy but slow-growing plant that can take many months to fill out in the garden.
Irish moss, unlike true moss species, doesn’t do well in full shade and wet conditions. Conversely, it also doesn’t appreciate extreme heat. It likes a sunny or partial shade position but intense heat isn’t good for this groundcover. In the right conditions though, this plant grows well and adds a rich and dense spread of color to your garden. Plant Irish moss in spring after your average last frost date. Space plants about 12 inches apart in well-draining soil and water them regularly.