Guilain Roussel is a landscaper with a degree from the École nationale supérieure du paysage de Versailles landscaping school, where he did his final year project on developing gardens in the general plan of the town of Aubervilliers. He is a co-founder of PG4, a collective of young landscapers committed to cultural and landscaping projects that place a special emphasis on including users’ opinions and doing field work and research. He is also president of the organization Frères Poussière, based in central Aubervilliers, which leads a series of social and cultural actions all focused around renovating an old theater. Since 2011 he has collaborated with Marjetica Potrč and RozO Architectes on the project La Semeuse, where he leads teaching workshops on introducing people to plants and raising their awareness about them, about material cycles and ecosystems. He has been an ideal collaborator for La Semeuse, bringing his landscaping expertise and intimate knowledge of the town to the table, leading the plant bank project and organizing conferences and discussions about the project.