Ambrosia artemisiifolia L.

English Common Ragweed, Bitterweed, Blackweed, American Wormwood ISEIA: C1
Lëtzebuergesch Alzem-Ambrosia EASIN
Français Ambroisie à feuilles d’armoise, ambroisie élevée, herbe à poux Wikipedia: Wikipedia - English - Common ragweed Wikipedia - Français - Ambroisie à feuilles d'armoise Wikipedia - Deutsch - Ambrosia Wikipedia - Nederlands - Alsemambrosia
Deutsch Beifußblättriges Traubenkraut, Ambrosia Wikispecies: Wikispecies - Ambrosia artemisiifolia
Nederlands Alsemambrosia Back to the list of neophytes

Report the species

Report Ambrosia artemisiifolia to the National Museum of Natural History.

Importance and distribution in Luxembourg

Distribution map of Ambrosia artemisiifolia L. in Luxembourg. Data source: Recorder-Lux & iNaturalist, 2019-09-21.

In Luxembourg, the first documentation of Ambrosia artemisiifolia in the wild 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).

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 source of origin of Ambrosia populations in Luxembourg. One large population (0.5 ha) of the plant was accidentally established in Kockelscheuer by a nature conservation organization 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.

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

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

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).

Bibliography concerning Luxembourg

  • 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]
  • 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, 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]

Leaflet on Ambrosia artemisiifolia

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

Video on Ambrosia artemisiifolia

The French Observatory of ragweeds has produced a 14-minutes-video on the issue of Ambrosia artemisiifolia for the general public, filmed during the summer of 2014 in France. Although made in France, this is a great movie showing many aspects of the ragweed problem, from biology to policy, including impressive images of endless ragweed fields! The films are accessible on Youtube in French and with English subtitles

Suggested citation of this webpage

Ries, C. & M. Pfeiffenschneider (Eds.), 2019. Ambrosia artemisiifolia L. In: - Invasive Alien Species in Luxembourg. National Museum of Natural History, Luxembourg. URL: [Accessed 2019-09-21].

 Last updated on Thursday, April 19, 2018.


  1. The population was reported on 24 November 2014 by Claudine Gengler via email. PhD student Yan Steil visited several times the place but the owners couldn’t be reached.
  2. After the report of the population by Claudine Gengler via phone in the beginning of July 2015, the following persons visited the population and searched the area for further occurrences on July 8th 2015: Christian Ries (MNHNL), Manou Pfeiffenschneider (efor-ersa), Tom Engel (ANF). Mr. Engel and his team eradicated the population shortly later. Three plants of 30 cm height have been reported by Claudine Gengler on October 14 2015.