Invasive pampas grass now found in over 200 Portuguese municipalities

Experts have warned that Cortaderia selloana, or pampas grass, is one of the most widespread and harmful invasive plants in mainland Portugal, present in at least 208 municipalities according to a 2025 study. Researcher Hélia Marchante said the species, banned since a 2019 decree-law from cultivation, sale and ornamental use, keeps spreading due to lack of enforcement. Beyond damaging ecosystems, its pollen can trigger a second autumn allergy season. Scientists criticised delays in publishing and implementing a national control plan and urged authorities and citizens to detect and remove new outbreaks early.