Ragweed (Ambrosia)

Ragweed Overview
Ragweeds (Ambrosia genus) are flowering plants in the aster family, native to the Americas, particularly the southwestern U.S. and northwestern Mexico. Some species have spread to Europe, becoming invasive due to climate change.

Description and Ecology
Ragweeds are annual or perennial plants growing from a few centimeters to over four meters tall. They produce wind-pollinated flowers and thrive in deserts, semi-deserts, and disturbed habitats.

Allergy Impact
Ragweed pollen is a leading allergen, causing half of pollen-related allergies in North America. A single plant can release a billion grains of pollen, which can travel long distances. Symptoms include sneezing, itching, and reactions to raw fruits and vegetables. Treatments include immunotherapy tablets.

Control and Management
Control methods include mowing, herbicides, and biological agents like beetles and fungi. Manual removal before flowering is also effective but may cause skin irritation.