The plant can help stop flash floods and pollution on roads, according to a new study based on experiences in Europe.
Replace the grass with moss on verges and embankments next to roads could become a natural solution to reduce pollution, slow down rainwater runoff and reinforce biodiversity, according to researchers and ongoing experiments in several European countries.
Currently, many slopes along highways in Europe are covered with grass, mainly to stabilize the soils and maintain a well-groomed appearance. But moss could offer more environmental advantages, at a time when several countries are looking for nature-based answers to face extreme phenomena and problems of environmental degradation.
Unlike grass, moss has no roots or flowers: it absorbs the water and minerals it needs directly from the atmosphere, allowing it to grow in thin soils, shaded areas and exposed surfaces where other plants have more difficulty surviving. Once installed, it requires little maintenance, as highlighted by the following: it grows slowly, stays close to the ground and would need to be cut much less frequently, which could reduce maintenance costs over thousands of kilometers of road.
One of the most studied characteristics of moss is its ability to capture atmospheric pollutantsincluding heavy metals, nitrogen compounds and fine particles typical of road traffic. It has been used as a bioindicator to monitor air quality in Europe for decades.
But in addition to pollution, moss can also help with water management.
Many species function as natural sponges, capable of absorbing several times their own weight in water and slowly releasing it. On road embankments, this can delay runoff during heavy rain, reducing pressure on drainage systems and the risk of flash floods, especially in urban or residential areas close to major roads.
The researchers also highlight the ecological potential of these areas. Berms and embankments can function as habitat corridors for insects, lichens, microorganisms and other species, especially in landscapes fragmented by agriculture or urbanization.
But experts also recognize that moss it is not a universal solution. It grows slowly, can take years to establish itself and not all species resist well to salt used to de-ice roads or prolonged periods of drought. Furthermore, the pollutants it absorbs are retained in plant material, which may require periodic monitoring and removal.
