A new study highlights how a simple plant like moss could play a powerful role in making roads more environmentally friendly, especially in regions facing rising pollution and extreme weather.
Across Europe, roadside embankments are usually covered with grass to stabilise soil and maintain a neat appearance. However, researchers now suggest that moss could be a more effective and sustainable alternative.
Unlike grass, moss does not rely on soil for nutrients. It absorbs water and minerals directly from the air, allowing it to grow in thin soils, shaded slopes, and exposed surfaces where grass often struggles. Once established, moss requires very little maintenance, as it grows slowly and does not need frequent cutting. This could significantly reduce maintenance costs along long stretches of highways.
One of the most important advantages of moss is its ability to absorb air pollution. Scientists have long used moss as a natural indicator of environmental quality because it can trap harmful substances such as heavy metals, nitrogen compounds, and particulate matter produced by traffic emissions. In fact, the European Moss Survey already uses moss to monitor pollution levels across multiple countries.
When planted along busy roads, moss could help capture some of these pollutants before they spread into nearby communities or ecosystems. This makes it a potential natural solution for improving air quality in urban and highway environments.
Moss also offers benefits in managing rainwater. Acting like a sponge, it can absorb several times its own weight in water and release it slowly. During heavy rainfall, this ability can help reduce the speed of water runoff from roads and embankments. Slower runoff means less pressure on drainage systems and a lower risk of flash flooding, which is becoming more common due to climate change.
In addition to pollution control and water management, moss can support biodiversity. Roadside areas often act as narrow ecological corridors, and moss-dominated surfaces can provide habitats for insects, microorganisms, and other small species. This could help improve ecological connectivity in landscapes affected by urbanisation and agriculture.
However, researchers caution that moss is not a universal solution. It grows slowly and may take years to establish fully. It also prefers cool, damp, and shaded environments, meaning it may not thrive on dry or sun-exposed roadside slopes. In addition, substances absorbed by moss, such as pollutants, remain stored within it, which may require monitoring over time.
Despite these challenges, the study suggests that rethinking how roadside vegetation is managed could bring significant environmental benefits. Instead of simply maintaining grass for appearance, roadsides could be designed to actively reduce pollution, manage water, and support ecosystems.
While moss may not transform highways overnight, small changes across thousands of kilometres of roads could collectively make a meaningful difference in tackling pollution, flooding, and climate-related challenges.