Himalayan knotweed	Status LU: absent.
	Himalaya-Knuetkraut	Status Eur.: established. 1st record: 1898. IAS of EU concern (2022).
	Renouée de l’Himalaya	RA: ISEIA: n/a Harmonia+: n/a
	Himalaja-Knöterich	Wikipedia: | Wikispecies: | CABI
	n/a	Back to the list of neophytes

Brief description

Koenigia polystachya (Wall. ex Meisn.) T.M. Schust. & Reveal, commonly known as Himalayan knotweed is a species of flowering plant in the knotweed family. The species is native to Asia (southwestern China, Indian Subcontinent, Myanmar, Afghanistan) and it is planted in many places as an ornamental. It has the capacity to become an invasive species and has established itself in some parts of North America, primarily the Pacific Coast of the United States and Canada, as well as in the UK and Belgium. It is an invasive weed in the mountains of Sri Lanka.

Koenigia polystachya is a rhizomatous perennial herb producing thick, hollow, erect stems easily exceeding one metre (40 inches) in length. Via its rhizomes it can form dense colonies. It may also spread asexually if sections of the stem containing rooting nodes are separated and moved to a new area; chopping the plant into small pieces does not necessarily keep it from growing. The hairy leaves are up to 20 centimetres (8 inches) long. The branching inflorescence is an array of lacy clusters of many small white flowers. Called thothnay in Sikkim and Darjeeling areas of India, the pleasantly sour-tasting edible shoots and stems are used as a vegetable or used to make piquant condiments and accompaniments for meals. (Wikipedia contributors 2021).

IAS of Union concern

First recorded in Europe in 1898 in Ostende (Groom 2011).

In 2022, Koenigia polystachyaetaceum (Forssk.) Chiov. was added to the list of invasive alien species of Union concern (Anonymous 2022) which implies that member states shall take all necessary steps to prevent its unintentional introduction or spread.

Status and distribution in Luxembourg

Koenigia polystachya (Wall. ex Meisn.) T.M.Schust. & Reveal has not yet been recorded in Luxembourg.

Risk assessment

ISEIA protocol

Not assessed yet.

Harmonia+ protocol

Not assessed yet.

Worldwide distribution

Bibliography

• Anonymous, 2022. Commission implementing regulation (EU) 2022/1203 of 12 July 2022 amending Implementing Regulation (EU) 2016/1141 to update the list of invasive alien species of Union concern. Official Journal of the European Union L 186: 10-13 (2022-07-13).
• CABI, 2010. Persicaria wallichii. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2022-08-19]
• Groom, Q., 2011. Rubrivena polystachya (Wall. ex Meissner) M. Král in: Manual of the Alien Plants of Belgium. Botanic Garden Meise, Belgium. At: alienplantsbelgium.be [accessed 2023-09-27] https://alienplantsbelgium.myspecies.info/content/rubrivena-polystachya
• Wikipedia contributors, 2022. ‘Koenigia polystachya’, Wikipedia, The Free Encyclopedia, 27 September 2019, 08:25 UTC, <https://en.wikipedia.org/wiki/Koenigia_polystachya> [accessed 2022-08-19]

 Page content last updated on 2023-09-27. Last proofread by Caroline Grounds on 2022-09-06.

	American pokeweed	Status LU: established. 1st record: LU <1946, ITW 1980.
	Amerikanesch Kermesbier	Status Eur.: established. 1st record: Med. ~1650.1
	Raisin d’Amérique, Teinturier	RA: ISEIA: B1, Watch List. Harmonia+: n/a.
	Amerikanische Kermesbeere	Wikipedia: Wikispecies: | CABI
	n/a	Back to the list of neophytes

Brief description

Phytolacca americana L. is widely naturalised in ruderal sites and in nature-like habitats in southern Europe, extending northwards to central France. Semi-natural habitats colonised include heaths, open woodlands, clearcut areas and forest edges. In Belgium, it is commonly used as an ornamental; it is planted in gardens and public green areas but doesn’t reproduce in the wild so far. Under suitable environmental conditions, the American pokeweed forms dense populations that can outcompete native vegetation and prevent regeneration of forest species. The plant produces toxic saponins (Branquart et al. 2010).

IAS of Union concern

In 2020, Phytolacca americana L. was proposed as a candidate species to join the list of invasive alien species of Union concern.

Status and distribution in Luxembourg

The oldest herbarium specimen at the Museum dates back to the 19th century: it is a specimen from Siebenbürgen from the A. Georges herbarium in Gotha found in the Koltz herbarium, probably an exchange specimen (Specimen № 15712, MNHNL 2000-).

The oldest reference to Phytolacca in Luxembourg is found in the Bulletin of the Luxembourg Naturalist Society, when Eugène Beck circulates a sample of Phytolacca […], known from some of Luxembourg City’s ornamental gardens (Anonyme 1946). We assume it to be Phytolacca americana L., as Phytolacca acinosa Roxb. has not yet been observed in Luxembourg. It was first recorded in Belgium in 1960 (Verloove 2021).

The first documentation of the American pokeweed in the wild was recorded in 1980 by Pierre Becker in a fir plantation downstream of Soup in the municipality of Heffingen (Reichling 1985: 136; Obs. key: DSS00465000000CI in MNHNL 2000-).

Grown for ornamental purposes in gardens. Very rare subspontaneous or adventitious; naturalised towards the SW limit of the Flora’s territory: roadsides, waste ground, … The fruits of this species are poisonous, unlike those of Phytolacca acinosa Roxb., which is also grown in gardens for ornamental purposes, but especially for its fruits used as a colouring agent (Lambinon & Verloove 2012: 122).

Risk assessment

ISEIA protocol

B1 (2+2+3+2) = Watch List. First assessed 2021-02-16 by C. Ries & Y. Krippel.

Harmonia+ protocol

Not assessed.

Worldwide distribution

Bibliography

• Anonyme, 1946. Comptes-rendus des séances de la Société des naturalistes luxembourgeois. Séances hebdomadaires du mois d’octobre 1946. Lundi, 24 octobre. Bulletin de la Société des Naturalistes Luxembourgeois 51 (2): 54.
• Balogh L. & M. Juhász, 2008. American and Chinese pokeweed (Phytolacca americana L., Ph. esculenta van Houtte). – In: Botta-Dukát Z. & Balogh L. (eds): The most important invasive plants in Hungary. HAS IEB, Vácrátót, pp. 37–42.
• Branquart, E., S. Vanderhoeven, W. Van Landuyt, F. Van Rossum & F. Verloove, 2010. Harmonia database: Phytolacca americana L. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2021-02-15]
• CABI, 2019. Phytolacca americana L. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2021-02-15]
• 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, 2000-. Phytolacca americana L. in Recorder-Lux, database on the natural heritage of the Grand Duchy of Luxembourg. Musée national d’histoire naturelle, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2021-02-15]
• Reichling, L. 1985. Travaux de la Société. Séance du 8 mars 1982. Bull. Soc. Nat. luxemb. 85: 135-136.
• 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, 2021. First records of 56 invasive alien vascular plants in Luxembourg. Bulletin de la Société des naturalistes luxembourgeois 123: 115-127. [PDF 241 KB]
• Verloove, F., 2021. Phytolacca acinosa Roxb. On: Manual of the Alien Plants of Belgium. Botanic Garden Meise, Belgium. At: alienplantsbelgium.be, accessed 2021-02-16.
  http://alienplantsbelgium.be/taxonomy/term/4773/descriptions

 Page content last updated on 2021-12-03. Last proofread by Caroline Grounds on 2021-03-03.

1. The species was introduced around 1650 into the Mediterranean area to be used as a dye-plant (Balogh & Juhász 2008).[↩]

	Crimson fountaingrass	Status LU: introduced. 1st record: LU 2019, ITW n/a.
	Afrikanescht Lanterbotzergras	Status Eur.: established. 1st record: unkn. IAS of EU concern (2017).
	n/a	RA: ISEIA: C1. Harmonia+: n/a
	Afrikanisches Lampenputzergras	Wikipedia: | Wikispecies: | CABI
	n/a	Back to the list of neophytes

Brief description

Pennisetum setaceum (Forssk.) Chiov., commonly known as crimson fountaingrass, is a C4 perennial bunch grass that is native to open, scrubby habitats in East Africa, tropical Africa, the Middle East and SW Asia. It has been introduced to many parts of the world as an ornamental plant, and has become an invasive species in some of them. It is drought-tolerant, grows fast, reaches 3 feet in height, and has many purple, plumose flower spikes. Fountaingrass has been introduced to the Canary Islands, Sicily, Sardinia, southern Spain, Australia, South Africa, Hawaii, the Western United States, California, southern Florida and New Caledonia. It thrives in warmer, drier areas and threatens many native species, with which it competes very effectively as an invasive species. It also tends to increase the risk of intense wildfires, to which it is well adapted, thus posing a further threat to certain native species (Wikipedia contributors 2019).

IAS of Union concern

In 2017, Pennisetum setaceum (Forssk.) Chiov. was added to the list of invasive alien species of Union concern (Anonymous 2017) which implies that member states shall take all necessary steps to prevent its unintentional introduction or spread.

Status and distribution in Luxembourg

Pennisetum setaceum (Forssk.) Chiov. was first recorded in Luxembourg in December 2019 in two public parks: two plantings (15 and 29 m²; 9 specimens) in the municipal park of Hesperange (Signoret 2020: 20) and 5 specimens in the Edouard André Municipal Park in Luxembourg City (ibidem: 24) (MNHNL, iNaturalist & GBIF, 2020).

Risk assessment

ISEIA protocol

C1 (3+2+2+1). First assessed 2021-02-16 by C. Ries & Y. Krippel.

Harmonia+ protocol

Not assesed yet.

Worldwide distribution

Bibliography

• Anonymous, 2017. Commission implementing regulation (EU) 2017/1263 of 12 July 2017 updating the list of invasive alien species of Union concern established by Implementing Regulation (EU) 2016/1141 pursuant to Regulation (EU) No 1143/2014 of the European Parliament and of the Council. Official Journal of the European Union L 182: 37-39 (13.7.2017).
• CABI, 2010. Pennisetum setaceum. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2020-03-04]
• MNHNL, iNaturalist & GBIF, 2020. Pennisetum setaceumin MNHNL-mdata, online portal combining species observation from Recorder-Lux, iNaturalist and GBIF. National Museum of Natural History, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2020-03-04]
• 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]
• Signoret, S., 2020. Inventaire d’espèces exotiques envahissantes dans des arboretums, jardins botaniques et parcs aménagés au Luxembourg. Étude réalisée pour l’Administration de la nature et des forêts, 57 p. [PDF 6MB]
• Wikipedia contributors, 2019. ‘Pennisetum setaceum’, Wikipedia, The Free Encyclopedia, 27 September 2019, 08:25 UTC, <https://en.wikipedia.org/w/index.php?title=Pennisetum_setaceum&oldid=918152552> [accessed 2020-03-04]

 Page content last updated on 2022-04-28. Last proofread by Caroline Grounds on 2020-03-05.

	Common milkweed	Status LU: uncertain. 1st record: LU & ITW <1836.
	Gewéinlech Seideplanz	Status Eur.: established. 1st record: unkn. IAS of EU concern (2017).
	Asclépiade commune	RA: ISEIA: B0, Alert List. Harmonia+: 0,19
	Gewöhnliche Seidenpflanze	Wikipedia: | Wikispecies: | CABI
	Gewoon zijdeplant	Back to the list of neophytes

Brief description

Asclepias syriaca L. originates from North America and is cultivated as an ornamental. It was introduced into European countries from France to Bulgaria and Russia (potentially invasive) (EPPO 2019). A. syriaca colonises a variety of communities from woodlands to cleared grasslands and marshlands. It grows in clumps or patches in meadows, fencerows, roadsides, railways, waste places, reduced-tillage fields, and other open habitats (CABI 2010). Larger populations can displace native plant and animal species, especially if the species penetrates into habitats worthy of protection. The large leaves shade the soil and thus prevent the emergence of other species (Anonymous 2014).

In 2014, Switzerland added Asclepias syriaca L. to its List of Invasive Alien Plants (EPPO 2019, Anonymous 2014).

IAS of Union concern

In 2017, Asclepias syriaca L. was added to the list of invasive alien species of Union concern (Anonymous 2017) which implies that member states shall take all necessary steps to prevent it’s unintentional introduction or spread.

Status and distribution in Luxembourg

Asclepias syriaca L. was first mentioned for Luxembourg by Tinant (1836: 134): “This plant, native to Syria and cultivated in our gardens, is found wild on the rocks around Bellevue [Ed.: Petrusse valley in Luxembourg City], where it is quite common […]. It also grows in the park of Clervaux.”¹ Klein (1897: 54-55) mentions the Common milkweed to be grown as an ornamental plant.

Lambinon & Verloove (2012: 534) mention this melliferous species as very rare in the territory of the flora; recently in expansion in Belgium.

The databases contain no observations of Asclepias syriaca L. for Luxembourg (MNHNL, iNaturalist & GBIF, 2020).

Risk assessment

ISEIA protocol

B0 (3+2+2+2) = Alert List. First assessed 22 November 2019 by Christian Ries.

Harmonia+ protocol

Overall risk score 0,19 = (Overall Invasion score 0,52 x Overall Impact score 0,37) (Ries et al. 2020).

Worldwide distribution

Bibliography

• Anonymous, 2014. Asclepias syriaca in: Info Flora – Das nationale Daten- und Informationszentrum der Schweizer Flora. URL: https://www.infoflora.ch/de/assets/content/documents/neophyten/inva_ascl_syr_d.pdf
• Anonymous, 2017. Commission implementing regulation (EU) 2017/1263 of 12 July 2017 updating the list of invasive alien species of Union concern established by Implementing Regulation (EU) 2016/1141 pursuant to Regulation (EU) No 1143/2014 of the European Parliament and of the Council. Official Journal of the European Union L 182: 37-39 (13.7.2017).
• CABI, 2010. Asclepias syriaca L. [original text by Claire Teeling]. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2019-11-22]
• EPPO, 2019. EPPO Global Database: Asclepias syriaca L. URL: https://gd.eppo.int [accessed 2019-11-22]
• Klein, E. J., 1897. Die Flora der Heimat (sowie die hauptsächlichsten bei uns kultivierten fremden Pflanzenarten biologisch betrachtet. Eine Anleitung zur selbständigen Beobachtung der Lebens- und Anpassungserscheinungen in der Pflanzenwelt). 552 S., Buchdruckerei Justin Schroell, Diekirch.
• 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, 2020. Asclepias syriaca in MNHNL-mdata, online portal combining species observation from Recorder-Lux, iNaturalist and GBIF. National Museum of Natural History, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2020-02-28]
• 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]
• Tinant, F. A., 1836. Flore luxembourgeoise, ou, Description des plantes phanérogames, recueillies et observées dans le grand-duché de Luxembourg, classées d’après le système sexuel de Linnée. 512 p. Luxembourg, J. P. Kuborn.

 Page content last updated on 2021-07-14. Last proofread by Caroline Grounds on 2019-11-27.

1. Original text: “Cette plante originaire de Syrie et cultivée dans nos jardins, se trouve sauvage sur les rochers aux environs de Bellevue, où elle est assez fréquente […]. Elle croît aussi dans le parc de Clervaux.”[↩]

	American skunk-cabbage, swamp lantern	Status LU: casual. 1st record: 2022
	Amerikanesch Heckepëppchen	Status Eur.: established. 1st record: UK 1901.1 IAS of EU concern (2016).
	Lysichiton américain	RA: ISEIA: B1, Watch List. Harmonia+: 0,14
	Amerikanischer Stinktierkohl	Wikipedia: | Wikispecies: | CABI
	Moeraslantaarn	Back to the list of neophytes

Brief description

Lysichiton americanus Hultén & H. St. John grows in the transition zone of terrestrial, semi-aquatic and aquatic habitats like swamps, fens, wet meadows, marshy and alluvial woodlands, along streams, riverbanks, lakesides and ponds. It has no specific site condition requirements except the presence of saturated organic soils. It is often found in protected semi-natural habitats. Lysichiton reproduces almost exclusively by seeds, which may be dispersed downstream along waterways. However, spread by natural means is not frequent and rather limited. L. americanus has become established locally in swamp forests and associated wetlands in the EPPO region (resulting most of the time from plantation in the site). After some years, its huge leaves build a dense layer excluding light from native species which are usually not adapted to extreme darkness. It can displace and cause local extinction of rare species of mosses and vascular plants (Carex echinata, Viola palustris, and orchids). (Branquart et al. 2010).

IAS of Union concern

In 2016, Lysichiton americanus Hultén & H. St. John was added to the list of invasive alien species of Union concern (Anonymous 2016) which implies that member states shall take all necessary steps to prevent it’s unintentional introduction or spread.

Status and distribution in Luxembourg

Lysichiton americanus Hultén & H. St. John was first documented by Christiane Wolff via iNaturalist on 2022-05-31 and was confirmed by Maximilien Oly on 2022-06-02 in the Mamer valley close to Kopstal. Three individuals have been differenciated next to a tributary of the Mamer. The small population was eradicated by the local forestry service. The origin of the population has not been identified.

Risk assessment

ISEIA protocol

B1 (2+3+3+2) = Watch List. First assessed 2019-01-24 by Manou Pfeiffenschneider and Christian Ries.

Harmonia+ protocol

Overall risk score 0,14 = (Overall Invasion score 0,34 x Overall Impact score 0,40) (Ries et al. 2020).

Worldwide distribution

Bibliography

• Anonymous, 2016. Commission implementing regulation (EU) 2016/1141 of 13 July 2016 adopting a list of invasive alien species of Union concern pursuant to Regulation (EU) No 1143/2014 of the European Parliament and of the Council. Official Journal of the European Union L 189: 4-5.
• Branquart, E., I. Stiers, S. Vanderhoeven, W. Van Landuyt, F. Van Rossum & F. Verloove, 2010. Harmonia database: Lysichiton americanus Hultén & H. St. John. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2019-11-21]
• CABI, 2021. Lysichiton americanus. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2021-03-04]
• MNHNL, iNaturalist & GBIF, 2020. Lysichiton americanus in MNHNL-mdata, online portal combining species observation from Recorder-Lux, iNaturalist and GBIF. National Museum of Natural History, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2020-03-02]
• Oly, M., 2022. Kartierung invasiver gebietsfremder Wasserpflanzen im Großherzotum Luxemburg, Untersuchungen zur Verbreitung von invasiven gebietsfremden Wasserpflanzen in einer beispielhaften Auswahl an Stillgewässern, Musée national d’histoire naturelle, Luxembourg. 117 pp. 
• 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]

 Page content last updated on 2023-08-17. Last proofread by Caroline Grounds on 2019-11-19.

1. Cf. CABI 2021.[↩]

	Creeping water primrose	Status LU: absent. 1st record: n/a.
	Krauchend Waasserprimmel	Status Eur.: established. 1st record: FR 1830s. 1 IAS of EU concern (2016).
	Jussie rampante	RA: ISEIA: A0, Alert List. Harmonia+: 0,44
	Kriechendes Heusenkraut	Wikipedia: | Wikispecies: | CABI
	Kleine waterteunisbloem	Back to the list of neophytes

Brief descritpion

Ludwigia peploides (Kunth.) P.H. Raven is an amphibious plant living in ponds, lakes, ditches, channels and slow-running rivers as well as in humid meadows. It shows a high tolerance to different water levels. Its growth is favoured by water eutrophication but the plant is able to develop in oligotrophic environments. Both clonal and sexual reproductions contribute to plant spread across watersheds. Water primroses are highly detrimental to the environment in western Europe. They quickly develop and make very thick monospecific floating carpets at the surface of water bodies. They alter the physico-chemical quality of water (reduction of light and dissolved oxygen) and possess an allelopathic activity that influences the water quality throughout the year and reduces the germination and survival rates of other plant species. They outcompete most native water plants and create an anoxic environment detrimental to many plant and animal species. In addition, they modify water flow and cause wetland drying (Branquart et al. 2013).

IAS of Union concern

In 2016, Ludwigia peploides (Kunth.) P.H. Raven was added to the list of invasive alien species of Union concern (Anonymous 2016) which implies that member states shall take all necessary steps to prevent it’s unintentional introduction or spread.

Status and distribution in Luxembourg

Ludwigia peploides (Kunth.) P.H. Raven has not yet been observed in Luxembourg (MNHNL, iNaturalist & GBIF 2020).

Risk assessment

ISEIA protocol

A0 (3+3+2+3) = Alert List. First assessed 24 January 2019 by Manou Pfeiffenschneider and Christian Ries.

Harmonia+ protocol

Overall risk score 0,44 = (Overall Invasion score 0,59 x Overall Impact score 0,75) (Ries et al. 2020).

Worldwide distribution

Bibliography

• Anonymous, 2016. Commission implementing regulation (EU) 2016/1141 of 13 July 2016 adopting a list of invasive alien species of Union concern pursuant to Regulation (EU) No 1143/2014 of the European Parliament and of the Council. Official Journal of the European Union L 189: 4-5.
• Branquart, E., S. Vanderhoeven, W. Van Landuyt, F. Van Rossum & F. Verloove, 2013. Harmonia database: Ludwigia peploides (Kunth.) P.H. Raven. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2019-11-21]
• CABI, 2021. Ludwigia peploides. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2021-03-04]
• MNHNL, iNaturalist & GBIF, 2020. Ludwigia peploides in MNHNL-mdata, online portal combining species observation from Recorder-Lux, iNaturalist and GBIF. National Museum of Natural History, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2020-03-02]
• 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]

 Page content last updated on 2021-03-04. Last proofread by Caroline Grounds on 2019-11-19.

	Water primrose	Status LU: absent. 1st record: n/a.
	Groussbléieg Waasserprimmel	Status Eur.: established. 1st record: FR 1830s.1 IAS of EU concern (2016).
	Jussie à grandes fleurs, Grande J.	RA: ISEIA: A0, Alert List. Harmonia+: 0,28
	Großblütiges Heusenkraut	Wikipedia: | Wikispecies: | CABI
	Waterteunisbloem	Back to the list of neophytes

Brief description

Ludwigia grandiflora (Michx.) Greuter & Burdet is an amphibious species living in ponds, lakes, ditches, channels and slow-running rivers as well as in humid meadows. It shows a high tolerance to different water levels. Its growth is favoured by water eutrophication but the plant is able to develop in oligotrophic environments. Invasive spread across watersheds is almost exclusively clonal and brought about by the dispersal of vegetative propagules by waterflow. Water primroses are highly detrimental to the environment in western Europe. They quickly develop and make very thick monospecific floating carpets at the surface of water bodies. They alter the physico-chemical quality of water (reduction of light and dissolved oxygen) and possess an allelopathic activity that influences the water quality throughout the year and reduces the germination and survival rates of other plant species. They outcompete most native water plants and create an anoxic environment detrimental to many plant and animal species. In addition, they modify water flow and cause wetland drying (Branquart et al. 2013).

IAS of Union concern

In 2016, Ludwigia grandiflora (Michx.) Greuter & Burdet was added to the list of invasive alien species of Union concern (Anonymous 2016) which implies that member states shall take all necessary steps to prevent it’s unintentional introduction or spread.

Status and distribution in Luxembourg

Ludwigia grandiflora (Michx.) Greuter & Burdet has not yet been observed in Luxembourg (MNHNL, iNaturalist & GBIF 2020).

Risk assessment

ISEIA protocol

A0 (3+3+2+3) = Alert List. First assessed 24 January 2019 by Manou Pfeiffenschneider and Christian Ries.

Harmonia+ protocol

Overall risk score 0,28 = (Overall Invasion score 0,46 x Overall Impact score 0,62) (Ries et al. 2020).

Worldwide distribution

Bibliography

• Anonymous, 2016. Commission implementing regulation (EU) 2016/1141 of 13 July 2016 adopting a list of invasive alien species of Union concern pursuant to Regulation (EU) No 1143/2014 of the European Parliament and of the Council. Official Journal of the European Union L 189: 4-5.
• Branquart, E., I. Stiers, S. Vanderhoeven, W. Van Landuyt, F. Van Rossum & F. Verloove, 2013. Harmonia database: Ludwigia grandiflora (Michx.) Greuter & Burdet. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2019-11-21]
• CABI, 2021. Ludwigia grandiflora. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2021-03-04]
• MNHNL, iNaturalist & GBIF, 2020. Ludwigia grandiflorain MNHNL-mdata, online portal combining species observation from Recorder-Lux, iNaturalist and GBIF. National Museum of Natural History, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2020-03-02]
• 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]

 Page content last updated on 2021-03-04. Last proofread by Caroline Grounds on 2019-11-19.

1. Cf. CABI 2021.[↩]