Sagina subulata
Irish moss
Common names: Pearlwort, Awl-leaved pearlwort, Star moss
At a glance
- Light
- Partial shade
- Pot size
- from 3 l
- Lifespan
- Perennial
- Flowering
- May–Aug
- Hardiness
- Hardy down to −25 °C
- Water need
- Medium
- Origin
- Native to Germany
Photo: Jerzy Opioła · CC BY-SA 4.0 · Source
This description was machine-translated.
Description
Star moss, botanically Sagina subulata, is despite its name not a moss but a flowering plant in the pink family (Caryophyllaceae). It forms a dense, evergreen mat of fine, needle-like leaves that grows only 2 to 5 cm high. The shoots creep and root at the nodes, so the mat closes over time on its own. From May to August, tiny white star-shaped flowers open on the mat. In the garden it replaces small lawn areas, fills the joints between stepping stones, and covers rock gardens, graves, and planters. It tolerates occasional walking, but it is too sensitive for a play lawn. In a partly shaded, fresh spot, and with some attention to watering, a closed, velvety green mat develops over time.
Care instructions
Plant star moss in spring or September in a bright, partly shaded spot. In full sun it needs considerably more water. Prepare the area thoroughly, since weeds growing between the clumps are later difficult to pull out. For joints between paving slabs, first fill the gaps with sandy soil. Set the divisions about 15 cm apart and press them firmly down. Keep the soil evenly slightly moist and water thoroughly during dry weeks, preferably in the morning. Brown patches in summer usually indicate drought stress, while in winter they are often caused by waterlogging. Cut them out and refill with divisions. In spring, carefully rake out leaves and brown remnants.
The care notes were machine-translated from German.
Garden year
SowingMar–Jun
FloweringMay–Aug
Germination
- Soil temperature
- from 10 °C, ideally 18 °C
- Days to sprout
- 14 to 28 days
- Light
- Needs light to sprout
- Sowing depth
- Press in, don't cover
- How to start
- Start indoors, then plant out
Soil & site
Soil pH
Soil type
well-drained, sandy, humus-rich
Irish moss grows in loose, free-draining soil that is both sandy and humus-rich and stays evenly fresh. A slightly acidic to neutral pH suits it well. Heavy, wet soils make the cushions rot, while severe drought turns them brown. Before planting, remove weeds and roots thoroughly; later, weeding between the tiny plants is tedious. On loam, mix in sand and a little compost.
Feeding
Light feeder
Months
Apr
Irish moss needs little. In April, sieve a thin layer of fine, mature compost between the cushions; this keeps the area dense and green. It needs nothing more, as too much food makes the cushion soft. In a container, replace the top layer of soil with fresh, sandy soil every spring.
Overwintering
Irish moss is hardy and stays green. In winters with little snow, hard frost and sun, individual patches can turn brown; in spring they usually shoot again. Then remove only leaves and dead remains and fill gaps with divisions. Wet winters are more critical than cold, so water should drain away well. In a container, protect the pot from constant rain against a house wall.
Propagation
Methods
- From seed
- Division
The easiest way is to divide Irish moss. In spring or late summer, detach small pieces from the edge of a cushion, set them on moist soil and press them down, and they will root quickly. This is how you fill gaps or create new areas. Sowing is also possible: the seeds are tiny, so mix them with a little sand, scatter them on fine soil from March and only press them in, as they need light to germinate. Keep the area evenly moist. Do not be surprised if the Irish moss later seeds itself into paving joints and neighbouring beds.
For your garden
Grow Irish moss yourself
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