France’s Regional Health Agency is calling for a collective effort at slowing the spread of ragweed and is urging members of the public to pull out the plants as soon as they are identified.
This North American plant, with its distinctive yellow flowers, has been spreading highly allergenic spores throughout Europe for the past century.
Ragweed is now present in all areas of metropolitan France, however the rate of proliferation varies greatly from one region to another.
In 2024, 74% of ragweed reports were made in the Auvergne-Rhône-Alpes region in the south-east of the country, according to the annual report written by environmental research network, Fredon France.
Ragweed can grow rapidly and survive in a range of environments including agricultural plots, riverbanks, roadsides, construction sites, and wasteland.
It poses a threat to farming and biodiversity, and also causes some people to experience allergic reactions.
Ragweed reactions
Ragweed releases its spores during the months of August and September.
While the plant itself is odourless, exposure to 10 spores per m² is enough to provoke an allergic reaction, which can include:
Ad
Rhinitis
Conjunctivitis
Swollen eyes
Asthmatic reactions
Rashes
These are best managed by over the counter treatments, such as antihistamines, decongestants and nasal sprays.
The plant is thought to cost between €59 million and €186 million per year in medical fees, including medication and consultations, states the French health authority ANSES, and up to 3.5 million people in France are thought to suffer from reactions to its pollen.
Reporting ragweed plants
If you find ragweed on your own property, you can remove the plant yourself as you can if you come across any small ragweed plants on public land.
Flowering ragweedElena Elisseeva / Shutterstock
This should ideally be done before the flowering period (between August and September) to avoid exposure to pollen, and gardening gloves should be worn. Make sure to remove the entire plant, including the roots.
See here for full details and advice on pulling out ragweed.
For extreme cases, France’s Regional Health Agency asks the public to report ragweed on the Signalement Ambroisie website or application. You can alternatively email contact@signalement-ambroisie.fr or call 09 72 37 68 88.
Over 8,300 alerts were received via this platform in 2024. These are communicated to local prefectures who can then intervene to ensure safe and effective removal of the plants.
Look out for the American Ragweed leaf beetle
When filing a report, you will also be asked to indicate whether the plant’s leaves have been eaten by insects. You should add one or two photos to the report, if possible.
Bite marks could indicate the presence of the American Ragweed leaf beetle, a key ragweed predator that could help curb the spread of the weed.
This insect was first identified in France in 2023, and was reported more than 70 times via Signalement Ambroisie in 2024.
Around 60 of these reports were verified and confirmed, with the beetle being detected in the southern departments of Rhône, Ain, Ardèche, Drôme, Isère, Vaucluse and Gard.
