Ambrosia artemisiifolia

Common Ragweed, hayfever weed, small ragweed, wild tansy, bitter weed, hogweed, wild wormwood, Roman wormwood, tassel weed, blackweed, stickweed, carrot weed, annual bur-sage

Description: summer annual

Place of origin: North America

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: Ambrosia 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 used the plant for medicinal purposes, for treatment of hives, fever, pneumonia, diarrhea, menstrual cramps, stroke, blood poisoning, swelling, nausea, and used it as an disinfectant. Ambrosia can be used for phytoremediation purposes.