Ambrosia artemisiifolia, common ragweed, is the most widespread plant of the genus Ambrosia in North America. It has also been called annual ragweed, bitterweed, blackweed, carrot weed, hay fever weed, Roman wormwood, stammerwort, stickweed, tassel weed, and American wormwood. It is native to North America but a widespread and common invasive weed in much of South America, Australia, and Eurasia.
The species name, artemisiifolia, is given because the leaves were thought to bear a resemblance to the leaves of Artemisia, the true wormwoods.
Common ragweed grows to about one meter (3 feet) in height. Its wind-dispersed pollen is a strong allergen to many people with hay fever. Common ragweed emerges in the late spring, and sets seed in later summer or fall.
Common ragweed is a very competitive weed and can produce yield losses in soybeans as high as 30%. Control with night tillage reduces emergence by around 45%. Small grains in rotation will also suppress common ragweed if they are overseeded with clover. Otherwise, the ragweed will grow and mature and produce seeds in the small grain stubble. As of 2005[update] several herbicides were effective against common ragweed, although resistant populations were known to exist. In 2007 several Ambrosia artemissifolia L. populations were glyphosate resistant, exclusively in the USA. 
SMARTER is a European interdisciplinary network of experts involved in the control of ragweed, health care professionals, aerobiologists, ecologists, economists, and atmospheric and agricultural modellers.
- Flora of North America Vol. 21 Page 15 Ambrosia artemisiifolia Linnaeus, Sp. Pl. 2: 988. 1753.
- Flora of China Vol. 20-21 Page 876, 877 豚草 tun cao Ambrosia artemisiifolia Linnaeus, Sp. Pl. 2: 988. 1753.
- Biota of North America Program 2014 county distribution map
- Hokche, O., P. E. Berry & O. Huber. (eds.) 2008. Nuevo Catálogo de la Flora Vascular de Venezuela 1–859. Fundación Instituto Botánico de Venezuela, Caracas.
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- Altervista Flora Italiana, Ambrosia artemisiifolia L.
- Atlas of Living Australia, Ambrosia artemisiifolia L. Annual Ragweed
- INRA - The common ragweed
- A. Davis, K. Renner, C. Sprague, L. Dyer, D. Mutch (2005). Integrated Weed Management. MSU.
- Stephen B Powles (April 2008). "Evolved glyphosate-resistant weeds around the world: lessons to be learnt". Pest Management Science Pest Management Science 64 (4): 360–365. doi:10.1002/ps.1525.
- Ophraella communa, the ragweed leaf beetle, has successfully landed in Europe: fortunate coincidence or threat? Weed Research, Volume 54, Issue 2, pages 109–119, April 2014, DOI: 10.1111/wre.12072
- Cf. www.ragweed.eu. The project runs from 2013 to 2017 in the frame of the EU programme COST. More than 120 participants from 33 countries are participating in 2013.
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- Jepson Manual Treatment
- USDA Plants Profile
- GRIN Species Profile
- Final report EC Assessing and controlling the spread and the effects of common ragweed in Europe
- North American ragweed to bring autumn allergy misery to Europe