Along the dunes of Vendée, between La Tranche-sur-Mer and the island of Noirmoutier, tall silver tufts of pampas grass have been swaying in the wind for over forty years. Originally a popular ornamental plant featured in French garden catalogs, pampas grass is now classified as an invasive species due to its negative environmental impact. A ministerial decree from March 2, 2023, prohibits its sale, possession, and transport across all of France, with severe penalties of up to three years in prison and a fine of 150,000 euros for violations. Pampas grass is known for its ability to produce an enormous number of seeds—up to one million per plant annually, with some larger specimens generating as many as ten million. These lightweight seeds are easily dispersed by the wind, traveling over a kilometer and colonizing new areas quickly. A single pair of pampas grass plants planted in a garden can, within a few seasons, spread throughout nearby dunes, transforming the landscape rapidly. Native to South America, pampas grass was introduced to Europe in the late 20th century. In its new environment, it had no natural predators or strong competitors to limit its spread. By the early 1980s, it had become permanently established along the Vendée coastline, where its preference for sandy soils and oceanic climate allowed it to thrive. In Brittany, a similar pattern emerged in the 1990s, with the plant first spreading through former industrial areas before moving toward coastal dunes, marshes, and roadsides. The dense growth of pampas grass can reach several meters in height, forming thick barriers that choke out native vegetation. It absorbs water and nutrients, reducing resources for local wildlife and degrading the habitats of many coastal species. Once dried, its biomass becomes highly flammable, increasing the risk of wildfires in areas where it is prevalent. In 2022, the European Union added pampas grass to its list of invasive alien species of concern, prompting France to implement the ban through a ministerial decree that took effect in April 2023. Although the law prohibits the sale and transport of pampas grass within France, some individuals and professionals still acquire it from neighboring countries like Italy, Germany, Belgium, or the Netherlands, where it remains legal. This cross-border movement complicates enforcement efforts. To combat the spread, environmental groups and local authorities are using a combination of manual removal before seed production, public awareness campaigns, and training for landscape workers. However, the damage caused by decades of unchecked growth is already significant in parts of the Vendée coastline. Now, the focus is not only on preventing further spread but also on restoring the damaged ecosystems, raising important questions about the long-term impact of introducing non-native plants into local environments.