Portugal Warns Homeowners—Especially Expats—to Remove Pampas Grass Before Seeds Fly

Visitors landing in Portugal at this time of year often marvel at the creamy plumes that sway along the A1 motorway and fringe many new housing developments. What most newcomers do not realize is that those feathery tufts belong to one of the country’s most troublesome invaders—and the count-down to contain it ends in just a few days.

Why the fluffy plumes you keep seeing are a serious threat

Step out of the car for a closer look and the scene changes. The same waist-high plumes admired by many expats release clouds of almost invisible seeds that ride the Atlantic breeze for kilometers. Each inflorescence of Cortaderia selloana—better known here as erva-das-pampas—can generate tens of thousands of wind-borne seeds. Once established, the grass forms razor-sharp leaves, out-competes local flora and, in dry weather, becomes a fire-accelerant. Portugal’s biodiversity agency has now placed the species on its National Red List of invasive aliens, classifying the current expansion as critical.

From garden ornament to nationwide headache

Imported from South America in the 1970s as a landscaping novelty, pampas grass quickly leapt beyond private gardens. Motorway verges, abandoned quarries and coastal dunes offered perfect launchpads. A study by the Polytechnic of Coimbra shows its range increasing by around 20% every two years, with densest outbreaks between Aveiro and Porto. Removal costs have spiralled; one regional council told reporters it spent €270,000 in 2024 alone just to clear a handful of industrial plots. Experts warn that allowing the plant to spread freely for another decade would add millions of euros in eradication bills and place several protected habitats on the verge of collapse.

What the law says—and what penalties you could face

Foreign residents occasionally buy ornamental grasses without realizing they may be illegal. Under Decreto-Lei 92/2019, pampas grass is banned from sale, transport and planting throughout Portugal. The more recent Law 45-A/2024 obliges landowners—private or commercial—to remove any mature stands discovered after inspections. Failure to comply can trigger administrative fines up to €20,000 and liability for any downstream environmental damage. Condominium boards and short-term rental hosts should therefore verify that common gardens or rooftop pots are not sheltering the plant; municipal inspectors are empowered to order immediate removal at the owner’s expense.

Health concerns many foreigners overlook

While seasoned residents dread the relentless spring pine pollen, few expect a second allergy wave in late summer. Research led by Coimbra biologist Hélia Marchante confirms that pampas grass pollen peaks between August and November, prolonging rhinitis and asthma episodes well into autumn. Hospitals in Porto district recorded a 17% increase in respiratory ER visits during last year’s plume season, with children and recent arrivals lacking prior exposure among the most affected. The plant’s stiff leaves also cause skin lacerations, an issue for gardeners and pets alike.

How Portugal is fighting back in 2025

This autumn the country is deploying its widest anti-pampas campaign yet. Two EU-funded initiatives—LIFE Coop Cortaderia and LIFE STOP Cortaderia—are mapping outbreaks, training local crews and testing biodegradable mulching membranes that smother regrowth after mechanical removal. The national environment ministry has set aside €5M through the Fundo Ambiental to bankroll municipal projects along the Lima and Minho rivers, where the grass threatens migratory-bird wetlands. Meanwhile, the conservation authority ICNF has released a user-friendly Manual de Boas Práticas in English and Portuguese, guiding landowners through safe eradication methods.

What you can do this week before seed season ends

Early action is still the cheapest fix. If you spot pampas grass on your property—or your neighbor’s—specialists advise severing the plume stalks before the end of September and sealing them in sturdy bags headed for landfill, never compost. Young plants shorter than 1 m can usually be pulled out with gloves and a spade, roots included. Residents without garden space can still help by logging sightings on the crowd-sourced portal Invasoras.pt or via the iNaturalist / Biodiversity4All mobile app; photographs and GPS coordinates feed directly into the national early-warning map. Crucially, do not rely on strimmers: cutting the leaves alone stimulates even denser regrowth next spring.

Local victories that prove removal works

Several municipalities have shown the battle is winnable. In Lousada, volunteer brigades eradicated 90% of recorded plants within the Sousa Superior protected landscape between 2021 and 2023, combining mechanical removal with three-year monitoring. Oliveira do Bairro turned the issue into a high-school science project, training teenagers to map infestations and replace cleared patches with native oak saplings. On the coast, Vila Nova de Gaia partners with Spanish and French researchers to pilot drones equipped with seed-detecting sensors, cutting survey time by half.

Looking ahead: the window is closing

Scientists estimate that if the current community-driven push can suppress new seed production for just five consecutive seasons, pampas grass will lose the momentum it needs to dominate Portugal’s landscapes. Conversely, ignoring the problem even for a single flowering cycle can undo years of progress. For foreigners planning to settle here long-term, learning to recognise—and act against—those picturesque plumes may become as routine as recycling glass or sorting compost. The next few weeks offer a decisive chance to keep Portugal’s dunes, riverbanks and garden plots free from an invader that, for all its charm, simply does not belong.