While some gardeners perceive the star moss (Sagina subulata), which sometimes colonizes wildly, as a nuisance in the lawn and fight it accordingly, other garden owners value it because of its pretty abundance of flowers with the characteristic star shape that gives it its name. Although the plant is generally considered to be rather short-lived, it is still hardy in most regions in this country without protection.
Is star moss hardy?
Star moss (Sagina subulata) is hardy and can tolerate temperatures down to -15 to -20 degrees Celsius for short periods of time. Overwintering outdoors is possible, but you should avoid covering it as the plant does not tolerate moisture build-up very well.
Overwintering the star moss properly outdoors
The star moss can also tolerate cold temperatures down to minus 15 or 20 degrees Celsius for a short time. Therefore, overwintering in the outdoor bed is possible without any problems in most locations. While other plants are often happy to be covered with a special protective fleece in winter, this can lead to problems with star moss: although the plant can have problems due to cold frosts in winters with little snow, it can only tolerate the moisture that accumulates under fleeces or a cover of leaves very bad. Therefore, the star moss is often easier to overwinter in partially shaded locations than in a sunny spot, as in partial shade there is more of a continuous snow cover with fewer major temperature fluctuations.
Which can cause plant damage to star moss in winter
The biggest enemy for star moss in winter is not frosty temperatures, but rather a build-up of moisture caused by soil that is too wet or covered with leaves and similar materials. Therefore, from locations under trees, remove any leaf cover before the first snowfall so that the risk of mold formation can be minimized. In spring, the star moss can be displaced when more dominant and faster-growing plants take over the “rudder” in the perennial bed or rock garden. Therefore, look out for potential wild weed growth early in the year and weed accordingly. The root rot that occurs on star moss in winter can be prevented by making heavy substrate at the site more permeable with a little gravel, sand or seasoned compost before planting.
Let the plants mature sufficiently before winter
An important factor for the ability to overwinter with star moss is the “maturity” of the plants; this can be influenced by the following factors:
- Time of sowing
- Planting time
- Fertilization
If the star moss is to be planted as a lawn replacement in the fall, this should not be done too late. The seeds should also be sown in good time so that they can develop into strong plants before winter. Fertilization for star moss should be completed around the end of July, otherwise it will not switch from the growth phase to hibernation in time.
Tip
If the star moss has bare spots in the middle of its cushions after winter, then this does not have to be due to the low temperatures. In spring, simply cut off parts of the star moss that are spreading to the sides and use them to fill in any bare areas.
