Helen Mark sets out on a pavement safari to find out how urban weeds are gaining more respect. She meets Jane Perrone and French botanist Sophie Leguil, who both draw people's attention to plants by chalking their names next to them. She also hears from Trevor Dines of Plantlife, who argues that grass verges should be mowed less frequently, allowing the wildflowers that line roads to grow and therefore enrich both the environment and people's well-being
