« Mauvaises herbes », qualité de l'eau et entretien des espaces

Résumé Fr En

Les plantes spontanées sont souvent jugées indésirables en ville et éliminées, du fait qu’elles ne répondent pas aux critères attendus dans les espaces urbains : l’ordre et la propreté. La volonté de réduire les pollutions par les produits chimiques conduit à mettre en place d’autres pratiques : soit laisser pousser, ce qui heurte les représentations sociales dominantes de l’espace urbain ; soit utiliser d’autres techniques que les herbicides. La réticence vis-à-vis de l’abandon de ces produits illustre les représentations dont ces techniques sont l’objet, perçues comme une manifestation de progrès. Les « mauvaises herbes » font aussi partie des relations socio-politiques entretenues au sein de la ville. Ainsi, les modalités techniques d’entretien mises en place sont-elles retraduites par les acteurs dans un registre sociopolitique.

Weeds, water quality and urban space management. Our paper studies the interconnections between phenomena that have seldom been considered simultaneously. Taking the example of weeds in a situation of changing maintenance methods in urban spaces, we show that technical choices are not only driven by technical but also by social and cultural considerations. Mental representations of urban spaces, categorization of plants, representations of techniques as well as political relations in the city are all closely interlinked. Changes in the maintenance and upkeep methods of urban spaces are dictated by the ecological context as well as by the social and cultural one. Changing techniques such as herbicide application therefore implies that the overall context is considered and not solely the technical factors. Spontaneous plants are often deemed undesirable in cities and eliminated because they do not conformto urban criteria of order and cleanliness. To avoid using chemicals, alternative practices can be applied: let the weeds be or use other eradication methods. However, professionals do not easily give up pesticides owing to cultural patterns such as the rule that a good worker does not leave weeds around or to beliefs about pesticides as a hallmark of progress. Weeds are also involved in the socio-political relationships of urban space. The technical methods used are socially interpreted: for instance letting weeds grow in a given area while they are eradicated in another is interpreted as a lack of interest by the municipality for people living in areas where weeds are not eliminated.