Many gardeners value star moss (Sagina subulata) with its small, star-shaped flowers as a green cushion in the rock garden or as a lawn replacement. However, when people talk about a “star moss infestation in the middle of the lawn,” they usually mean another plant.
How to fight star moss in the lawn?
To effectively combat star moss in the lawn, you should aerate the soil with a scarifier, use special iron fertilizer and pluck out the moss manually. Maintain thick grass growth by adjusting the cutting height when mowing and select environmentally appropriate grass seeds.
The star moss (Sagina subulata) as a plant in the garden
The so-called star moss or polewort is a hardy plant that is often used to green cracks in walls, paving joints and rock gardens. The plant grows in the form of round cushions and can spread laterally in a location so that paved paths or walls are partially covered by it. If this is the case, cutting off with a spade is relatively easy. Even self-sowing the very fine seeds does not usually cause problems with star moss (Sagina subulata), as it is extremely weak against other “weeds” and plants in the garden.
Effectively fight moss in the lawn
Strictly speaking, the milkweed of the genus Sagina, known as star moss, is not actually a moss, but is a member of the carnation family. The actual type of moss, which is often colloquially referred to as star moss due to the shape of the plant, is usually the beautiful Widerton moss or maidenhair moss (Polytrichum formosum). This can sometimes actually become an aesthetic problem for a lawn if certain criteria for its spread are met. These are for example:
- a rather acidic pH value of the soil
- a compacted and therefore permanently moist soil
- poorly ventilated soil substrate
- not very dense turf
As a countermeasure against a high proportion of moss in the lawn, you can aerate the subsoil with a scarifier (€119.00 on Amazon), attack the moss with a special iron fertilizer (mosses are low-feeders) or even the moss in places manually pluck and sow new grass seeds.
Prevent moss infestation when creating a new lawn
If you want to create a new lawn in your garden or have no other way to deal with the moss problem, you can use a well-thought-out approach to create a lawn without moss or with a small amount of moss. Loosen heavy soil and apply a permeable layer of compost and sand to loamy subsoil. Avoid overcompacting the lawn and choose grass seeds that can handle a possible lack of direct sunlight.
Tip
The wider clay moss (Polytrichum formosum) is less likely to gain a foothold in the lawn if you ensure dense grass growth with a medium cutting height when mowing. Absolutely shady and very moist areas are sometimes suitable for planting star moss (Sagina subulata) as an easy-care lawn replacement.