GREENER CITIES

A guide to the plants on our pavements

Pesticide-FREE

We are in the midst of a biodiversity crisis and it is vital that we take action to ensure our towns, cities and other urban areas are havens for wildlife. This guide aims to provide a better understanding of the plants that grow on our streets and pavements, how they help to mitigate biodiversity loss, and how they contribute to making the places where we live, work, and play flourishing spaces for all.

Most councils in the UK still look to maintain a ‘neat and tidy’ approach on our streets, parks, and playgrounds, or where any weeds grow. Sadly, the term ‘weed’ has a pejorative connotation for what is effectively just a flower or plant in the wrong place. Yet, these plants play a valuable role in supporting bees, pollinators, birds, and many other species that forage or shelter on them. And many have their own intrinsic beauty that can bring joy to those of us that are lucky enough to see them.

In this guide, we outline why going pesticide-free and allowing for more natural, urban plant growth are key elements in creating more resilient towns and cities. Urban botanist, Dr Amanda Tuke, takes us through some of the many plants that thrive on our streets and provides an insight into their importance, what makes them unique and how to look out for some unusual species living quite literally on our doorsteps.

Going pesticidefree and allowing nature to thrive does not need to result in overgrown streets that compromise on accessibility.

Rather, a nuanced approach which recognises the need to keep pavements clear for health and safety reasons, but also encourages wildlife in the right places, is recommended. Our cities can be both well maintained and thriving with biodiversity, but it takes imaginative designing, attentive planning, and dedicated maintenance to be successful.

We hope to encourage elected councillors, council officers and residents to be more accepting of the wonderful variety of plants growing in our urban spaces, and aware of their enormous benefits for biodiversity. We also hope that this guide will encourage councils to include pesticide phase-outs in their nature recovery and/or biodiversity strategies, and to rethink their ‘weed management’ plans.

Why go pesticide-free?

The main reason for using urban pesticides is cosmetic. They are sprayed around schools, hospitals, housing estates, shopping centres, on road verges and pavements, as well as cemeteries, public gardens and sports pitches, including golf courses. Every year, hundreds of tonnes of pesticides are used in these open spaces of our towns and cities. At last count, there were a reported 38 different types of pesticide used, and while this list includes fungicides and insecticides, the majority are herbicides, with glyphosate-based herbicides being by far the most common.

When used on hard surfaces, such as pavements and paths, pesticides can run off into water courses, harming aquatic wildlife in the process. Herbicides turn parks into ‘green deserts’ where only turf grass grows. They kill plants which are relied upon by insects, birds and other wildlife. Some pesticides are also highly persistent meaning that they reside in soil long into the future.

Do weeds damage pavements?

There is a common misconception that any plant that grows on a pavement is going to cause it damage. However, it is rare that plants are the root of the problem. Damaged infrastructure is most often the result of weather-related issues such as the ‘freezethaw’ cycle in which water seeps into small cracks and then freezes and expands.

It is important for councils to take a proactive, yearround approach when maintaining pavements and outdoor spaces in order to address these issues. Rather than allowing plants to grow in the spring and summer and then having to remove them, it is critical that during autumn and winter councils clear accumulated detritus from cracks, edges, and gutters. This detritus is made up of plants and leaves breaking down into organic matter, creating fertile soil for the next season of plants to grow. It has also been shown to exacerbate cracks in pavements as the trapped humidity over time weakens the integrity of the concrete.

As a result, the overuse of pesticides is destroying many of the areas where wildlife can forage for food and contaminating the natural resources they depend upon. A 2017 study1 conducted in nature reserves across Germany revealed a 76% decline in flying insects since 1990. Pollinators, such as wild bees, are particularly struggling. In Eastern England, known as one of the richest regions for bees in Britain, 17 bee species have gone extinct while another 25 species are at risk of extinction2 Providing space and habitat for insects and other wildlife in our towns and cities is vital.

Pesticides are also toxic to people, and children, in particular, are more vulnerable to the long-term effects of pesticide exposure. Glyphosate has been linked to a number of diseases, from cancers such as leukaemia and non-Hodgkin’s Lymphoma, to the development of Parkinson’s disease, and other chronic health conditions such as asthma.

Exposing people, wildlife and the environment to these toxic chemicals is unnecessary.

Local authorities have a legal duty to keep pavements clear of detritus – section 89 of the Environmental Protection Act 1990 imposes a Duty to Keep Land and Highways Clear of Litter and Refuse3

A focus on measures that prevent plants establishing in the first place will save councils considerable amount of time and effort and reduces the need for weeding.