Ambrosia artemisiifolia L.

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English Common Ragweed Status LU: established. 1st record: LU 1949, ITW 1950.
Lëtzebuergesch Alzem-Ambrosia Status Eur.: established. 1st record: NL 1860.
Français Ambroisie à feuilles d’armoise RA: ISEIA: C1. Harmonia+: 0.54
Deutsch Beifußblättriges Traubenkraut, Ambrosia Wikipedia: Wikipedia - English - Common ragweed Wikipedia - Français - Ambroisie à feuilles d'armoise Wikipedia - Deutsch - Ambrosia Wikipedia - Nederlands - Alsemambrosia | Wikispecies: Wikispecies - Ambrosia artemisiifolia | CABI
Nederlands Alsemambrosia Back to the list of neophytes

Report the species

Report Ambrosia artemisiifolia to the National Museum of Natural History.

Brief description

Ambrosia on a private parking spot in Dalheim (08/07/2015).

Ambrosia on a private parking spot in Dalheim (08/07/2015).

Ambrosia artemisiifolia L. is an opportunistic and ruderal plant that colonises farmlands, fallow lands and road embankments. Ambrosia prefers warm areas and light, nutrient-rich soil deprived of vegetation. The common ragweed is unlikely to outcompete other plant species as it mainly colonises soil without vegetation. It is a public health hazard as it commonly causes allergies (rhinitis, asthma…) and is a weed in cereal fields (Branquart et al. 2010).

Status and distribution in Luxembourg

Records of Ambrosia artemisiifolia L. in Luxembourg. Data source: Recorder-Lux, iNaturalist & GBIF, 2022-01-21.

In Luxembourg, the first documentation of Ambrosia artemisiifolia L. dates from 1949. It was found on 6th October 1949 in a garden in Helmsange (Municipality of Walferdange) and determined as Ambrosia elatior L. (synonym) by the Belgian botanist André Lawalrée (Beck et al. 1950).

The species was next recorded in the wild by Léopold Reichling (1921-2009) on 5 September 1950 in a waste ground in Neudorf, Luxembourg City (Obs. key: DSS004390000166M, MNHNL 2000-).

Nowadays, the species is considered as quite rare to rare (AR-R), expanding in the territory of the flora (Lambinon & Verloove 2012: 716).

Luxembourg belongs to one of the few remaining European areas with a very low distribution of Ambrosia artemisiifolia.

In his diploma thesis, Patrick Thommes (2008) had a closer look at the occurrence of common ragweed in Luxembourg, at its germination rate and its ability to produce viable seeds and at the contamination rate of bird food with Ambrosia seeds.

Contaminated bird food is the main origin of Ambrosia populations in Luxembourg. One large population (0.5 ha) of the plant was accidentally established in Kockelscheuer by a nature conservation organisation a few years ago when seeding a sunflower field for a visitor centre. Measures to eradicate the population have been ongoing since 2012, but show only partial success. Flowering meadow mixtures appear to be a new pathway, having been the source of a population discovered in 2014 in a garden in Wasserbillig.

A large population was discovered on a private parking spot in Dalheim in October 2014 – these plants might originate from seeds transported by car wheels, the owner using the spot being a frequent traveller to France. 1 The population was reported again in 2015 and eradicated right away. 2

Steil et al. (2015) looked again at common ragweed seeds in bird food in Luxembourg in 2014 and compared the results with earlier studies by Thommes (2008, 2009), conducted in 2007, and by Ries et al. (2013), conducted in 2012. Between 2007 and 2014, the number of contaminated samples decreased in most types of products.

The Museum represented Luxembourg in an interdisciplinary network of experts involved in the control of ragweed, health care professionals, aerobiologists, ecologists, economists, and atmospheric and agricultural modelers. More than 120 participants from 33 countries were participating in SMARTER (2013-2017), the acronym for Sustainable Management of Ambrosia artemisiifolia in Europe ( SMARTER was a COST project funded by the EU.

Risk assessment

ISEIA protocol

C1 (2+1+2+1) (Ries et al. 2013: 18).

Harmonia+ protocol

Overall risk score 0,54 = (Overall Invasion score 0,54 x Overall Impact score 1,00) (Ries et al. 2020).


Worldwide distribution

Fact sheet and leaflet

PDF fact sheet of the Nature and Forestry Administration: FR | DE

In autumn 2016 the Department for the Environment of the Luxembourg Ministry of Sustainable Development and Infrastructures published a leaflet in German and French about Ambrosia artemisiifolia, in co-operation with the National Museum of Natural History and efor-ersa ingénieurs-conseils. It can be downloaded here in PDF format (4 MB each).

flyer-cover-de   flyer-cover-fr

Other Ambrosia species

  • Ambrosia psilostachya DC. was found in a stone quarry between Bridel and “Croix des Bourgeois” in the summer of 1947 and published under the synonym Ambrosia coronopifolia Torr. & A.Gray (Beck et al. 1950: 204).
  • Ambrosia trifida L. was found on rubble in Luxembourg City on 1950-08-17 (Beck et al. 1951: 171).


  • Anonymous (2015) Beifussblättrige Ambrosie – Eine invasive Art mit Risiken für Allergiker. Regulus 4/2015: 14-15. [PDF 246 KB]
  • Beck, E., Jungblut, F., Lefort, F.L., Reichling, L., Stumper, R., 1950. Herborisations faites dans le Grand-Duché de Luxembourg en 1949 (av. 2 fig. et 7 planches). Bull. Soc. Nat. luxemb. 54: 161-208. [PDF 1745 KB]
  • Beck, E., Jungblut, F., Lefort, F.L., Reichling, L., Stumper, R., 1951. Herborisations faites au Grand-Duché de Luxembourg en 1950 (av. 10 planches). Bulletin de la Société des naturalistes luxembourgeois 55: 121-174. [PDF]
  • Branquart, E., S. Vanderhoeven, W. Van Landuyt, F. Van Rossum & F. Verloove, 2010. Harmonia database: Ambrosia artemisiifolia L. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: [accessed on 2019-10-23]
  • CABI, 2016. Ambrosia artemisiifolia L. [original text by Duilio Iamonico]. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: [accessed 2020-02-28]
  • Lambinon J. & F. Verloove, 2012. Nouvelle flore de la Belgique, du grand-duché de Luxembourg, du Nord de la France et des régions voisines. Sixième édition. Avec la collaboration de L. Delvosalle, B. Toussaint, D. Geerinck, I. Hoste, F. Van Rossum, B. Cornier, R. Schumacker, A. Vanderpoorten et H. Vannerom. Jardin botanique national de Belgique, Meise. CXXXIX + 1195 pp. ISBN : 9789072619884.
  • MNHNL, iNaturalist & GBIF, 2019. Ambrosia artemisiifolia L. in MNHNL-mdata, online portal combining species observation from Recorder-Lux, iNaturalist and GBIF. National Museum of Natural History, Luxembourg. URL: [Accessed 2020-02-28]
  • Ries, C., 2017. Ambrosia artemisiifolia in Luxemburg. PowerPoint-Präsentation. Fachtagung Ambrosiabekämpfung – Rechtliche Rahmenbedingungen und Praxiserfahrungen, 2. Februar 2017, Bayerische Landesregierung, München. [PDF 536 KB]
  • Ries, C. & Y. Krippel, 2021. First records of 56 invasive alien vascular plants in Luxembourg. Bulletin de la Société des naturalistes luxembourgeois 123: 115-127. [PDF 241 KB]
  • Ries, C., Y. Krippel & M. Pfeiffenschneider, 2020. Risk assessment after the Harmonia+ protocol of invasive alien vascular plant species in Luxembourg. Bull. Soc. Nat. luxemb. 122: 197-205. [PDF 132 KB]
  • Ries, C., Y. Krippel, M. Pfeiffenschneider & S. Schneider, 2013. Environmental impact assessment and black, watch and alert list classification after the ISEIA Protocol of non-native vascular plant species in Luxembourg. Bull. Soc. Nat. luxemb. 114: 15-21. [PDF 652 KB]
  • Ries C, Y Steil & P Thommes (2013) Common ragweed (Ambrosia artemisiifolia L.) seeds in bird food in Luxembourg in 2007 and 2012. Poster. XXXe réunion annuelle des collaborateurs scientifiques du Musée national d’histoire naturelle Luxembourg, 16.03.2013. [PDF 1.5 MB]
  • Steil, Y., H. Vetter, P. Thommes & C. Ries, 2015. Ambrosia artemisiifolia L. seeds in bird food in Luxembourg: a comparative study, 2007 to 2014. Bull. Soc. Nat. luxemb. 117: 11-15. [PDF 151 KB]
  • Thommes P (2008) Ambrosia artemisiifolia L.: Ein potentiell invasiver Neophyt für Luxemburg. Unpublished diploma thesis. 76 p. [PDF 12 MB]
  • Thommes P (2009) Ambrosia artemisiifolia L. (Asteraceae), ein potentiell invasiver Neophyt für Luxemburg. Bull. Soc. Nat. luxemb. 110: 101-107. [PDF 265 KB]

 Page content last updated on 2021-03-02. Last proofread by Caroline Grounds on 2019-11-13.