Sagina subulata 'Aurea' Picture courtesy Karen Maraj from flickrCondensed Version:

Irish moss is renowned for planting between pavers but is very versatile in the garden. It forms a thick and dense mound of tiny yellow-green leaves, and although it only grows a couple of centimetres high, it can spread 30cm or more. The tiny translucent white flowers appear anytime from late spring to summer. What is commonly called "Irish Moss" (Sagina subulata) has rich emerald green leaves whilst the cultivar called "Scotch Moss" (Sagina subulata 'Aurea') is vibrant chartreuse.

Sagina does well in temperate gardens and thrives in cool, somewhat dry environments. It grows well in most parts of South Africa, and is cold and frost hardy. Although it likes a bit of humidity it can struggle in very humid regions, where the plants will 'melt-out' in the mid-summer heat, only reviving again in autumn. In dry and hot summer rainfall regions the plant will appreciate moderate watering and some shade during the heat of the day, and in the winter rainfall regions regular summer watering is required.

Athough Sagina thrives in gravelly well-drained soils it will adapt to most garden soils. It dislikes both drought and soggy, wet soils, so try to keep the plants evenly moist, watering before the soil dries out completely. Fertilise sparingly with liquid fertilisers, and weed carefully by hand.

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Description, History & Interesting Facts:

Sagina subulata, commonly called “The Heath Pearlwort” “Irish Moss”, “Awl-leaf Pearlwort” or “Scottish Moss”, is a species of flowering plant in the pink and carnation family, Caryophyllaceae. It is an evergreen perennial groundcover which is native to Europe, from Iceland south to Spain, and east to southern Sweden and Romania.

In the wild it can be found growing on dry, sandy or gravelly soils, and although not a true moss, it forms a thick and dense mound of tiny yellow-green leaves, and although it only grows a couple of centimetres high, it can spread 30cm or more. The tiny translucent white flowers are slightly fragrant, and they make their appearance individually on erect stems that can measure up to 3cm in height, appearing anytime from late spring to summer.

What is commonly called "Irish Moss" (Sagina subulata) has rich emerald green leaves whilst the cultivar called "Scotch Moss" (Sagina subulata 'Aurea') is vibrant chartreuse.

In the Garden:

Don't worry about treadling lightly on Irish moss as it will bounce right back from occasional damage, and its soft and cushy texture makes it perfect to grow a meditation cushion with, perhaps at the end of a barefoot-friendly pathway. The delicate nature of this plant also makes it a favourite for fairy gardens and petite dish gardens.

Although delicate looking, Irish moss is tough and also great for blanketing the ground around flagstones or along the edges of gravel pathways where other plants sometimes struggle to grow, or to simply form a soft carpet amongst boulders in rock gardens or around water features.

It’s even wonderful for dry stone walls, and works well as a groundcover around potted garden and patio plants, or for a minimalist look, plant Irish moss on its own in a row of small pots – simply perfect!

Sagina subulata Picture courtesy Brigitte Rieser from FlickrCultivation/Propagation:

Sagina does well in temperate gardens and thrives in cool, somewhat dry environments. It grows well in most parts of South Africa, and is cold and frost hardy, with minor winter browning in severely cold areas.

Although it likes a bit of humidity it can struggle in very humid regions, where the plants will 'melt-out' in the mid-summer heat, only reviving again in autumn. In these regions it’s vital that the soil has sharp drainage, and its best to keep the plants a bit on the dry side when humidity is high.

In dry and hot summer rainfall regions the plant will appreciate moderate watering and some shade during the heat of the day, and in the winter rainfall regions regular summer watering is required.

When we think 'moss' we think of plants that love moisture, but remember that Sagina in not a true moss and it dislikes both drought and soggy, wet soils, so the trick is to water moderately but regularly during long dry spells. Try to keep the plants evenly moist, watering before the soil dries out completely.

Athough Sagina thrives in gravelly well-drained soils it will adapt to most garden soils, even clay that drains. Adding some compost to very poor and sandy soils will be beneficial, as well as to amend clay soils for better drainage.

Fertilise sparingly with liquid fertilisers, and to keep the plants compact, avoid high nitrogen levels which can induce excessive foliar growth, so the plants become mounded rather than forming a flat carpet.

Weeds and grass can occasionally break through the tightly growing moss, threatening the health of the plant and disrupting the overall aesthetic. Pull them out by hand when they are still small, as pulling up established weeds will often damage the moss.

Weeding thoroughly and then covering the planting site with a black plastic sheet for up to three months before planting time will help to smother a lot of weed seeds before you plant or sow.

These plants can be propagated from seed or division, but for the average gardener it’s easiest to divide existing plants or those purchased at a garden centre. Division is best done in spring, by cutting narrow strips from established plantings, or digging out whole clumps to separate into pieces, ensuring that all pieces have roots for replanting.

Irish moss grows at a moderate rate and it may take several years to completely fill an area, so use many small, closely-spaced transplants to cover large areas more quickly. Ensure that the soil is kept moist until the plants are established.

Seeds can be started indoors several weeks before the average last frost date, or they can be sown directly into well-prepared beds in spring. Keep the soil evenly moist until germination, which can take 2 to 3 weeks.

Problems, Pests & Diseases:

Sagina is generally a trouble-free, durable plant, though like any plant, it is susceptible to a few pests and cultural problems. Fungal diseases are rare, but the plant is susceptible in very humid climates.

Poorly draining soil will contribute to root rot and other complications.

If over-watered, the plant may rot, but if it’s not watered enough, it may form dry, dead patches.

Fungus gnats or aphids may attack weakened specimens grown on overly moist soil.

Sagina may be attacked by slugs, which can be killed by placing a cup or bowl of beer, or other fermented liquid, next to the moss. Slugs find this irresistible, and land up inside the container, but are unable to get out.

Moles tunnelling under the moss may lift the plant, causing the roots to become dislodged. The moss must be carefully patted down back into the soil, or bare, dead patches will form.

Parts of the moss may die due to pet urine, excess fertiliser, or accidental herbicide exposure.

Warning:

Handling the plant may cause skin irritation or allergic reaction, and pollen may also cause allergic reactions.