Irish Moss is a low growing, evergreen, perennial groundcover in the carnation family with deep green moss-like leaves and tiny white daisy-like flowers. It forms a dense mat of slender stems that root at the nodes and tolerates moderate foot traffic. Irish Moss does best in moderately fertile, acid to neutral soil, in full sun with some midday shade. It does not do well in intense heat or drought and over watering can be a problem. The plant prefers cool, moist conditions and rocky or sandy soil. Most vegetative growth occurs during the spring while the weather is moist and cool. The plant tolerates light foot traffic and is good for filling in gaps in paving as well as rock gardens, and troughs. It would make a good lawn alternative planted along pathways or between stepping stones. The root system consists of a slender taproot that is shallow and divides frequently into secondary roots. This plant spreads by reseeding itself and it often forms small colonies of plants with a mossy appearance. Diseases, Insect Pests, and Other Plant Problems: Generally disease and pest free, but can be susceptible to aphids.
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
Clay; Loam (Silt); Sand; Shallow Rocky
Soil pH
Acid (<6.0); Neutral (6.0-8.0)
Soil drainage
Good Drainage | Moist
NC region
Coastal; Mountains; Piedmont
Growth rate
Medium
Maintenance
Medium
Canopy layer
5 - Groundcover
Form & Appearance
Habit / form
Dense; Spreading
Texture
Fine
Foliage
Needled Evergreen
Leaf color
Green
Leaf type
Needles
Leaf arrangement
Opposite
Leaf shape
Linear
Leaf margin
Entire
Leaf size
< 1 inch long
Hairs present
Yes
Leaf detail
Thin leaves, 1/2 to 1 inch in length, that can form dense mats. Pairs of leaves occur at intervals along the stems. Each pair merges together and wraps around the stem, which is slightly swollen where each pair of leaves occurs.
Flower color
White
Flower value
Fragrant; Showy
Flower form
Cyme
Flower shape
Wheel
Flower size
< 1 inch
Flower detail
Daisy-like white flowers with an attractive fragrance bloom in the spring.
Bloom time
Spring; Summer
Fruit color
White
Fruit type
Capsule
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
The ovoid seed capsule is white and membranous with 4 blunt teeth along its upper rim. Each capsule contains several dark tiny seeds that can be blown about by the wind. The surface of each seed is minutely pebbly.
Stem color
Green
Stem detail
One or more stems develop from a rosette of leaves. These stems are bright green, glabrous, and tend to sprawl across other stems or the ground.
Wildlife & Ecology
Native status
Unknown
Origin
Chile to Argentina and the Falkland Islands
Distribution
Introduced to the east and west coasts of United States (Oregon and Virginia)