Swiss railways test low-growing plant mix to replace herbicides

Keystone / Gaetan Bally

To reduce herbicide use in managing vegetation along railway tracks, the Swiss Federal Railways commissioned Agroscope and the Geneva-based School of Landscape, Engineering and Architecture (Hepia) to develop low-growing plant mixtures. After five years of trials, the method is now considered viable.

The Swiss Federal Railways aims to minimise the use of synthetic herbicides – specifically glyphosate – while ensuring that infrastructure longevity, safety and accessibility are not compromised, AgroscopeExternal link said in a press release last week.

To meet these goals, Agroscope, Hepia and additional partners conducted a study to identify plant covers that would suppress problematic weeds, support infrastructure safety, and boost biodiversity. Importantly, the selected species also had to avoid introducing any plants harmful to agriculture.

Five seed mixtures tailored for this purpose were tested at six locations across the Swiss Plateau. The species were selected to meet strict safety requirements: low growth height, shallow roots, no tripping hazards, clear signal visibility, and unimpeded drainage. All plants had to be native to Switzerland.

Success depends on location and seed mix

The trials demonstrated that it is possible to successfully revegetate railway tracks and embankments using these mixtures. The selected seeds met safety standards, enhanced biodiversity, lowered soil temperatures, and improved landscape quality.

Two of the mixtures – one designed for broad ecological adaptability and another rich in pioneer species – achieved average ground cover of more than 70% after five years on suitable soils. Across all sites, sown species were more dominant than volunteer species.

Problematic native plants and invasive species (neophytes) were significantly less common than both the sown and non-invasive volunteer species. Overall, biodiversity increased by an average of five species per site.

Maintenance requirements unchanged

The study concludes that revegetating trackside areas is a realistic and ecologically beneficial alternative to using herbicides. However, maintenance demands will not decrease: even with targeted planting, regular upkeep remains necessary.

Climbing plants such as ivy and brambles, as well as tall-growing or invasive species, still require monitoring. Future strategies may involve a combination of mechanical, chemical and biological methods to achieve long-term sustainability, Agroscope concluded.

Translated from French using DeepL/amva/ts