Common names (selected) English: annual bur-sage, bitter weed, blackweed, carrot weed, hayfever weed, hogweed, ragweed, Roman wormwood, short ragweed, small ragweed, stammerwort, stickweed, tassel weed, wild tansy, wild wormwood; Chinese: 豚草属 (ragweed); Finnish: marunatuoksukki; French: absinthe du Canada; ambrosie a feuilles d'armoise, l'ambroisie, petite herbe á poux; Latvian: vermellapu ambrozija; Lithuanian: kietine ambrozija; Polish: ambrozja bylicowata; Portuguese: ambrosia-americana, cravorana, losna-selvagem (Brazil), losna-do-campo (Portugal); Spanish: altamisa, amargosa, ambrosia de hojas de ajenjo, artemisia de terra, estafiate; Russian (transliterated): ambrosia polinnolistnaja

Description: Summer annual

Native regions and distribution: Native to Central and North America but currently found across the world particularly in temperate regions, introduced as a contaminant in seed and grains.

Urban habitat: Commonly found in vacant lots, rubble dumps, cultivated landscapes and lawns, roadsides, pavement openings, neglected public parks and at woodland edges; thrives in moist, dry and compacted soils; can tolerate road salt.

Ecological function: Disturbance-adapted colonizer, food for wildlife, absorbs heavy metals from soil.

History / human uses: The name Ambrosia means food of the gods. Pigs and sheep will consume it, thus its common name hogweed. A. artemisiifolia is the most widespread plant of the genus Ambrosia in North America and is a common cause of hayfever for many people in the late summer and early fall when the plant produces abundant pollen. Ragweed has been found to produce more pollen in environments with elevated CO2, suggesting that the plant will become a more serious allergy problem in the future. Although native to North America, the plant is usually considered undesirable. It is currently considered an invasive threat in many European countries and in Japan. A number of Native American tribes, including Cherokee, Dakota, Delaware, Houma, and Lakota, used the plant for medicinal purposes, for treatment of hives, fever, pneumonia, diarrhea, menstrual cramps, stroke, blood poisoning, swelling, nausea, and used it as a disinfectant. Ragweed can be used for phytoremediation purposes to remove heavy metals from soil.