Growing Native Plants on Boulevards Supports Local Biodiversity

By Jaime Clifton-Ross, Communications and Outreach Curator, National Environmental Treasure

Transforming boulevards into ecological havens filled with native plants, wildflowers, trees, and shrubs supports local biodiversity.

Boulevards are everywhere. In fact, your neighbourhood is likely surrounded by them. Also known as road verges, berms, swales, and curb strips depending on where you live, boulevards are patches of grass or plants lining roadways and sidewalks throughout urban and agricultural areas. One study in the Journal of Applied Ecology estimates that boulevards may cover up to 270,000 km2 of land across the world (0.2% of land). While 0.2% seems pretty small, this is actually a considerable amount of land. And a lot of it is likely not supporting biodiversity.

How can boulevards support biodiversity?

Many boulevards and manicured lawns are ecological dead zones, meaning they offer little in the way for wildlife like food and habitat. Yet boulevards are ubiquitous across Canada. Transforming these undervalued patches of land into ecological havens filled with native plants, wildflowers, trees, and/or shrubs is low-hanging fruit when it comes to supporting biodiversity.

If managed strategically, nature-full boulevards can increase biodiversity and support important systems in nature known as ecosystem services, including pollination. They create wildlife corridors that support animal movement while helping to mitigate the negative environmental impacts of our roadways like pollution and habitat fragmentation. They also beautify our roadways while increasing and supporting biodiversity in urban areas. Once plant biodiversity is teeming along boulevards, many other kinds of wildlife will be attracted to this new habitat including pollinators, frogs, snakes, and birds.

Native wildflowers rewild boulevards along Dorset, UK highway

One of the most famous wildlife-friendly boulevards is along a highway in Dorset, UK. Crucial and ancient wildflower meadow ecosystems in the UK largely vanished after World War II as a result of industrialization, pollution, and poor land management. A team in Dorset set out to transform the boulevards, filled with thick clumps of grass and invasive species, into biodiverse wildlife corridors with low-growing wildflowers. To maintain the land, they used a centuries-old haymaking practice known as the ‘cut and collect, lower fertility method’. This method requires less year-long maintenance as verges are only cut twice a year and clippings are removed “to gradually reduce the fertility of the soil and prevent a buildup of mulch”.

After implementing this strategy, the Weymouth relief road in Dorset county was completed in 2011. This 4.5-mile stretch with 17 acres of boulevards lines one of the busiest roadways in the United Kingdom. As a crucial site for biodiversity, its boulevards now attract numerous pollinators, including over half of Britain’s known butterfly species. This project also lowered maintenance costs from £1m to £350k over five years. PlantLife released guidelines for managing grassland roads verges in the UK. If implemented across the country, this boulevard strategy will help meet the country’s land restoration targets.

While specific types of wildflowers successfully rewilded boulevards in the UK, it’s important to note that wildflowers, shrubs, and trees selected for boulevards should be native to the area (in other words, non-invasive) and enhance local biodiversity. Planting and maintenance strategies should also be informed by specific habitat conditions and localized planting best practices.

How can you support boulevard gardening in your neighbourhood or community?

1. Participate in community boulevard gardening programs. The City of Victoria hosts ‘Get Growing Victoria’, an initiative that provides seedlings and gardening materials to people disproportionately impacted by the pandemic and who are facing food insecurity. While this initiative primarily focuses on edible plants, consider integrating native plants into your boulevard garden.

2. Learn about plants that are native to your area that support local wildlife. Check out Habitat Acquisition Trust’s ‘Gardening with Native Plants Guide’ and the Nature Conservancy of Canada’s blog about gardening with native plants for inspiration

3. Write a letter or email to your local government expressing your support for replacing monoculture grass on boulevards with native plants and inquire about their plans to support local biodiversity. 

4. Listen to our podcast episode with Dr. Sheila Colla about Native Bees and how to support them.