Irish and Scotch Moss, Sagina subulata and Arenaria verna

Scotch moss has gold to chartreuse foliage (L) while Irish moss is dark green. (R)

Irish and Scotch moss are prostrate herbaceous evergreen perennials in the carnation family (Caryophyllaceae) that superficially resemble moss. They are, however, flowering plants that thrive in full sun to partial shade rather than the moist, shady conditions where true mosses are found (mosses are primitive, non-flowering plants). The common name Irish moss generally refers to plants with emerald-green leaves, while Scotch moss is generally used for cultivars with gold to chartreuse foliage. The species most commonly offered commercially is Sagina subulata, a native of western and central Europe that is hardy in zones 4-8. It is also sometimes referred to as heath pearlwort. Arenaria verna, also called moss sandwort, is also from Europe and hardy in zones 4-7. The two are virtually indistinguishable when not in bloom (the flowers of S. subulata are solitary while those of A. verna are borne in small clusters) and both have golden forms, and the names are often applied incorrectly in the horticultural trade.

Both species make dense, compact mats of ground-hugging foliage spreading to a foot or more wide and just 1-2 inches tall. Tufts of slender, subulate (awl-shaped) leaves cover thin, creeping stems.

The dense mats of foliage (L) have thin, creeping stems (C) covered with narrow leaves (R).

Tiny star-shaped flowers are produced beginning in late spring and appear sporadically throughout the growing season. Rounded green buds on skinny stalks open to expose the 5 rounded white petals the same length as the pointed green sepals and ten white stamens. The flowers are sprinkled individually across the mat of leaves in S. subulata, but occur in clusters on A. verna. These are followed by tiny smooth, brown, triangular seeds in oblong capsules. Under good conditions they will readily self-sow, but is easy to remove where unwanted.

The small flowers (RC) are held above the foliage (L) on thin stalks (LC). The flowers are followed by brown fruits (capsules) that contain many smooth brown seeds (R).

Use Irish and Scotch moss where a very low, fine-textured carpet of green or gold is desired, such as around stepping stones, between flagstones, or at the edges of a path as they tolerate light foot traffic. In areas where there is heavy foot traffic, creeping thyme (Thymus serpyllum) is a tougher alternative that will stand up to being walked on more frequently. These plants can be a good groundcover near the edges of water features or in rock gardens. Use Irish or Scotch moss for contrast in smaller containers or to simulate a lawn in miniature or fairy gardens. The bright chartreuse-yellow color of Scotch moss provides a brilliant contrast with plants with darker green foliage. Green or golden forms can be used as a ground cover around smaller spring flowering bulbs such as crocus, snowdrops (Galanthus), or small fritillarias (such as Fritillaria michailovskyi or F. meleagris). Trying to create a patchwork or checkerboard of the green and gold types is a real challenge as they readily grow together to dilute the effect.

Irish or Scotch moss growing around rocks in a garden (L), as an accent in a mixed container (C) and as “grass” in a miniature garden (R).

Irish or Scotch moss is susceptible to browning out with too much or too little water.

Irish and Scotch moss grow best in full sun in the Midwest with regular water and excellent drainage. They will grow in partial shade, but will not be as compact here; in more southern areas they may need some afternoon shade. Fertilize sparingly to keep plants compact; high nitrogen levels can induce excessive foliar growth so the plants become mounded rather than forming a carpet. Water if necessary to keep evenly moist, but not wet. These plants have few pests, but slugs can damage the plants. The plants may be short-lived and clumps are susceptible to browning out with insufficient or excessive water.

Irish and Scotch moss are easily propagated from seed or division.

These plants can be propagated from seed or division. Cut narrow strips from established plantings or dig whole clumps and separate into pieces (being sure all have roots) for replanting. Plants grow at a moderate rate and make take several years to completely fill an area. Use many closely-spaced small transplants to cover large areas more quickly. Seeds can be started indoors several weeks before the average date of last frost, or direct sown in the garden in spring. Keep continuously moist as seeds will take 2-3 weeks to germinate.

– Susan Mahr, University of Wisconsin – Madison


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Additional Information

  • Scotch moss – on the University of Illinois From the Ground Up website

28 comments

  1. These are cute , little plants for sure. I have heard of them, but haven’t grown them myself. They seem easy to care for. I do wonder how well they stand up to wear thought with foot traffic.

  2. It was an interesting article. Never thought of a moss for sun. It’s also interesting that they are part of the carnation family. I’ve got some spots they might do nicely in.

  3. Mosses are in the Carnation Family! Wow! This is as surprising as palm trees belonging to the grass family! Plants are amazing! I’ll have to look for these plants. Currently, I use creeping thyme but am always looking for variety.

  4. Very useful information. I had no idea that there are mossy plants that tolerate sun.

  5. Interesting that the two are totally different colors and grow in the sun, not shade. I would never have thought a moss would be in the carnation family.

  6. Love the bright green color of this moss! I didn’t know that it was part of the carnation family. May try this in a few areas that seem like they could use this type of plant.

  7. I am always looking for ways to fill in empty spots but am blessed with 3 black walnut trees out back! I wonder if this could survive juglone. I began researching but haven’t found an answer yet.

  8. Interesting the ‘mosses’ are part of the carnation family.
    I have started them from seed in the greenhouse…
    they start out slow, but fill in nicely by May.
    Sun and don’t let dry out too much is right!
    Thanks for sharing your knowledge, Susan Mahr!

  9. I’ve planted the scotch moss in a rock wall years ago. It didnt survive. Not sure if it was the severe winter, living in northern Wisconsin, or not the right amout of water? No mention of deer liking it or not. Dont think that was the problem. I sure like the texture of this plant, though. Good article.

  10. I was planning on putting moss between some stepping stones, but now see I should plant the creeping thyme (Thymus serpyllum) as it is better for traffic areas and that will be my path to my vegetable garden. So glad I read this article.

  11. It is interesting that they are part of the carnation family. You would think “Irish or Scotch moss” would need shade-so it is good to know they need full sun to partial. I will keep this in mind for future plantings.

  12. I, too, wanted to grow Irish Moss in a partial shade location and to no avail. I will be working on a sunnier area this year and hope the dogs do not take a liking to it. I use a pre-emergent such as Preen to prevent weeds in stone areas of my garden. A walk-through once you see plants growing above moss height are easy to spot and pluck before they take over.

  13. I will be planting Irish moss seeds between and around my flagstone pavers on my very sunny patio. I have planted creeping thyme there before, but it really was too tall and looked messy.
    Good article.

  14. Grows well here. Nice substitute for moss. Does move but not quickly.

  15. I’m wondering if this will grow in northern Wisconsin. I’m a little reluctant with it being a zone 4, but a comment from another reader says she planted it in 3b and it grows, so maybe I’ll give it a try.

    • I have grown it for years and I live in Cumberland, near Rice Lake. An easy to grow substitute for moss. I tried growing it between pavers. It does nicely, but sometimes difficult to get weeds out that grows in between. Spreads pretty easily, but can be restrained fairly easily.

  16. I will plant the Irish Moss seeds in a 6foot by 14 foot path with patches of mulch and stepping stones of rock..great info here. a nice idea and doable for us.

  17. I tried planted Irish Moss this summer from a seed catalog. So far not much luck. The planting area is above a rock wall, well drained and mostly sunny to light shade. Not sure what went wrong but the live plants received from the catalog were not in the best condition.

  18. I just purchased a 6-pack of the Irish/Scotch moss at Stein’s in Waukesha. I wish I would have seen this article a week sooner as I should have planted them in a sunnier location rather than on the footpath in partial shade where I did. Will dig them up and transplant. This article was really helpful as the tag on the pot did not list much info at all.

  19. I planted Irish Moss between pavers in my garden in 2005 and they are still there. Nice plant. Some nurseries used to call this plant and others “Stepables” because they take some foot traffic.

  20. I planted two Sagina subulata ‘Aurea’ in a partial sun situation, but that was not enough sun to make them happy in Madison and they have since died. Would try again in a sunnier spot as the color is really nice.

  21. Interesting stuff. I have a lot of shade and a lot of different types of true moss. My granddaughters love to dig it up and plant it where we build their fairy gardens. This would be very pretty because of the flowering but with my lack of sun, I’m thinking I should stick with what grows naturally…..true moss.

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