The Friday Blog | Rethinking Roadside Design: How Moss Could Transform Climate Resilience and Air Quality on Our Highways

Across the UK and much of Europe, roadside verges and motorway embankments are an overlooked but extensive part of our infrastructure landscape.

Traditionally, these spaces have been planted with grass—largely for erosion control and aesthetic uniformity. But as climate pressures intensify and cities grapple with air pollution and flooding, it may be time to rethink this approach.

What if these thousands of kilometres of roadside land could do more than just look tidy? What if they could actively reduce pollution, manage stormwater, and support biodiversity?

Emerging research suggests that moss—often dismissed as insignificant—could play a surprisingly powerful role in achieving these goals.

The Case for Nature-Based Infrastructure

Infrastructure design is undergoing a quiet revolution. Increasingly, engineers and policymakers are turning to nature-based solutions—approaches that work with natural systems rather than against them.

Road networks, particularly in countries like the UK with dense transport infrastructure, present a unique opportunity. These linear corridors cut through urban, suburban, and rural landscapes, creating vast areas of managed land. Yet most of this land is underutilised from an environmental perspective.

Grass verges, while functional, offer limited benefits beyond basic soil stabilisation. They require frequent mowing, provide modest ecological value, and do little to address pressing challenges like air pollution or surface water management.

Moss, by contrast, offers a fundamentally different set of capabilities.

A Low-Maintenance Alternative with High Impact

Mosses are among the simplest land plants, lacking roots and instead absorbing water and nutrients directly from the atmosphere. This unique biology allows them to thrive in environments where grass struggles—thin soils, shaded slopes, and exposed surfaces.

From an infrastructure perspective, this is significant.

Once established, moss requires minimal maintenance. It grows slowly, remains low to the ground, and does not require regular cutting. Across a national road network, this could translate into substantial reductions in maintenance costs, fuel use, and associated emissions from mowing operations.

In an era where asset owners are under pressure to deliver both cost efficiency and sustainability, such dual benefits are hard to ignore.

Tackling Air Pollution at the Roadside

Perhaps the most compelling argument for moss lies in its ability to interact with the atmosphere.

Unlike most plants, mosses absorb substances directly from the air, including pollutants. For decades, scientists have used moss as a bioindicator to monitor environmental quality. Across Europe, large-scale surveys have relied on moss samples to track the distribution of pollutants such as nitrogen compounds, heavy metals, and particulate matter.

These are precisely the pollutants generated by road traffic.

If deployed strategically along busy transport corridors, moss could act as a passive filtration system—capturing airborne particles before they disperse into surrounding communities.

This is particularly relevant in urban and peri-urban areas, where roads often run close to residential zones, schools, and workplaces. While moss alone will not solve air pollution, it could form part of a broader mitigation strategy—complementing emissions reductions and technological interventions.

A Natural Solution to Surface Water Management

Flooding is another growing challenge for road networks.

Climate change is increasing the frequency and intensity of heavy rainfall events, placing pressure on drainage systems that were not designed for such extremes. Rapid runoff from impermeable surfaces like roads can overwhelm infrastructure, leading to localised flooding and wider network disruption.

Here, moss offers a quietly effective solution.

Many moss species function like natural sponges, capable of absorbing several times their own weight in water. Crucially, they release this water slowly over time.

On roadside embankments, this characteristic could help delay and reduce runoff, easing the burden on drainage systems during peak rainfall events. By slowing the movement of water into drains and culverts, moss-covered slopes could contribute to more resilient infrastructure.

In regions like the UK—where road density is high and many routes pass through flood-prone areas—such incremental improvements could have significant cumulative effects.

Enhancing Biodiversity Along Transport Corridors

Beyond pollution and water management, roadside environments play an important ecological role.

Road verges and embankments form long, continuous corridors that can support a range of species. In landscapes fragmented by agriculture or urban development, these corridors can act as vital links between habitats.

Moss-dominated environments add another layer of ecological value.

They create microhabitats that retain moisture and provide shelter for invertebrates, fungi, and microorganisms. While research into moss-specific roadside ecosystems is still developing, increasing structural diversity along verges is widely recognised as beneficial for biodiversity.

Incorporating moss into roadside design could therefore support broader environmental objectives, including national biodiversity targets and nature recovery strategies.

Where Moss Works Best—and Where It Doesn’t

Despite its potential, moss is not a universal solution.

It thrives in cool, damp, and shaded conditions—environments commonly found in parts of the UK and northern Europe, particularly along cuttings, wooded areas, and north-facing slopes. In these locations, moss could outperform grass both environmentally and economically.

However, challenges remain.

Moss establishes slowly, meaning that achieving full coverage on new embankments may take several years. It is also sensitive to certain environmental stressors. Road salt used in winter maintenance can damage moss, while prolonged dry conditions may limit its viability on exposed, sunlit slopes.

Another consideration is pollutant accumulation. While moss captures airborne contaminants, these remain within the plant tissue. Over time, this may require monitoring and potentially managed removal to prevent re-release into the environment.

These limitations highlight the need for targeted application rather than blanket adoption. Moss should be seen as one tool within a broader palette of roadside vegetation strategies.

From Maintenance Burden to Environmental Asset

The broader implication of this discussion is a shift in mindset.

For decades, roadside land has been treated as a maintenance liability—something to be controlled, cut, and kept tidy. But as environmental pressures mount, this perspective is becoming increasingly outdated.

Road networks occupy vast areas of land. If managed differently, they could become active environmental assets—helping to reduce pollution, manage water, and support ecosystems.

Moss offers a tangible example of how this transformation might begin.

It is not a high-tech solution. It does not require complex infrastructure or significant capital investment. Yet its cumulative impact—across thousands of kilometres of roadside—could be meaningful.

A Role for Innovation and Policy

Realising this potential will require collaboration between engineers, ecologists, policymakers, and asset managers.

Pilot projects will be essential to understand how moss performs in real-world roadside conditions. Standards and guidance may need to evolve to accommodate alternative vegetation strategies. Procurement frameworks could incentivise nature-based solutions as part of routine maintenance and renewal programmes.

There is also an opportunity for innovation—combining moss with other green infrastructure approaches, such as bioswales, permeable surfaces, and urban greening initiatives.

Crucially, success will depend on recognising that small changes at scale matter.

Looking Ahead

Moss will not transform highways overnight. Nor will it replace all existing vegetation. But it represents a shift towards more thoughtful, multifunctional infrastructure design.

In the face of climate change, air pollution, and biodiversity loss, incremental improvements across large systems can deliver significant benefits.

Sometimes, the most effective solutions are not the most complex or costly—but the ones that have been quietly growing at the edges all along.

As we rethink the future of our road networks, it may be time to give moss the attention it deserves.