Common ragweed (Ambrosia artemisiifolia) is native to North America and invasive in Europe. In Poland it is unevenly distributed, more often in the south and south-west and on disturbed sites such as roadsides, railways, building sites, and vacant land. Its range changes, so risk should not be judged only from a plant map.
Season and identification
Ragweed usually pollinates from August to September, sometimes into early October during a warm autumn. Its light pollen can travel from distant stands. It is easily confused with mugwort: ragweed leaves are green on both sides, while mugwort leaves often have a paler, silvery underside. Do not rely on that shortcut alone when removing an unknown plant; seek local advice if needed.
Symptoms include sneezing, a watery runny nose, nasal blockage, itchy eyes, and cough; asthma symptoms can worsen. Ragweed has a low reference threshold in the model, but the score cannot predict an individual response.
CAMS and limitations
The Polish city forecast uses CAMS through Open-Meteo. Values are modeled, not measured at a local station and are orientative. See the score algorithm, including the ragweed threshold and weather effects.
What can you do?
Check the forecast before working on vacant land, do not mow flowering ragweed without protection, and report infestations to your municipality under its local procedure. Wash your hands and change clothes after contact. A doctor or pharmacist should advise on medication; sudden breathlessness or throat swelling needs urgent help.
Sources: DWD, CAMS. This article is informational, not medical advice.