Egeria densa Planch.

English Large-flowered waterweed ISEIA: A1 – Black List
Lëtzebuergesch Dichtbliedreg Waasserpescht EASIN
Français Égérie Wikipedia: Wikipedia - English - Large-flowered waterweed Wikipedia - Deutsch - Dichtblättrige Wasserpest Wikipedia - Nederlands - Egeria (plant)
Deutsch Dichtblättrige Wasserpest Wikispecies: Wikispecies - Egeria densa
Nederlands Egeria (plant) Back to the list of neophytes

Report the species

Report Egeria densa to the National Museum of Natural History.

Importance and distribution in Luxembourg

Distribution map of Egeria densa Planch. in Luxembourg. Recorder-LUX & iNaturalist, 2019.08.21.

The species has been observed twice in 2016 in the Eisch valley East of Hobscheid (

The large-flowered water weed is an aquatic plant with a very wide ecological amplitude. It thrives in a variety of freshwater habitats: while it prefers flowing systems it may also be found in still waters. The species is not light demanding and is able to develop in deep and turbid waters. The submerged perennial makes dense monospecific populations which often colonize whole water bodies, restrict water movement, cut off light, produce anoxic conditions and trap sediments in the system. The large-flowered water weed has been reported to outcompete native aquatic plants and to adversely affect fish communities (Source:

Risk assessment

ISEIA protocol: A1 (2+3+3+3) = Black List. Updated on 22 June 2018 by Christian Ries and Manou Pfeiffenschneider. Former assessment: A0 (2+3+3+3) = Alert List (Ries et al. 2013: 18).

Bibliography concerning Luxembourg

  • 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]

Suggested citation of this webpage

Ries, C. & M. Pfeiffenschneider (Eds.), 2019. Egeria densa Planch. In: - Invasive Alien Species in Luxembourg. URL: [21.08.2019].

 Last updated on Monday, June 25, 2018.