Tall annual willowherb	Status LU: n/a. 1st record: 2021, ITW: 2021.
	Kuerzfriichteg Weideréischen	Status Eur.: n/a. 1st record: 1978.
	Épilobe d’automne	RA: ISEIA: n/a Harmonia+: n/a
	Kurzfrüchtiges Weidenröschen	Wikipedia: | Wikispecies: | CABI
	Wijde basterdwederik	Back to the list of neophytes

Brief description

Epilobium brachycarpum C.Presl.,  is a species of willowherb known by the common names tall willowherb, tall annual willowherb, panicled willowherb and tall fireweed. It is native to and widespread in North America, where it is a resident of varied open and woodland habitats. It has also been introduced to some areas in South America and Europe. E. brachycarpum is a tall glandular, hairy annual herb occasionally reaching two metres in height. The flower has four petals which may be so deeply notched that they look like four pairs. They are generally light purple or pink, with darker veining. The fruit is a capsule 1 to 3 cm long.

It grows in wasteland, disturbed areas, sunny sites, on stony ground. It is a pioneer species, in the process of establishing itself in Europe (Germany, France, Belgium, The Netherlands, Luxembourg,…). The distribution map from CABI as indicated here below is thus to be considered as incomplete. The plant seems to be spreading along roads and particularly railways. In its native range, it grows on dry or seasonally moist, often disturbed soil, in open woods, meadows, especially along roadsides, and riverbanks, up to an altitude of 3300 m. (Wikipedia contributors 2022, Wolff & Krippel 2022).

Status and distribution in Luxembourg

Epilobium brachycarpum C.Presl. was recorded for the first time in Luxembourg in 2021 on a worksite in the locality of Grevels. A second record of the species was made in the same year on a worksite in Eschdorf.

The various populations of E. brachycarpum observed during that year have been found on fallow land that has been uncultivated for a maximum of three years and were linked to construction works around Esch-sur-Sûre (drinking water treatment plant and new SEBES pipeline) (Wolff & Krippel 2022).

Risk assessment

ISEIA protocol

Not assessed yet.

Harmonia+ protocol

Not assessed yet.

Worldwide distribution

Bibliography

• CABI, 2019. Epilobium brachycarpum. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2022-08-22]
• Wikipedia contributors, 2022. ‘Epilobium brachycarpum’, Wikipedia, The Free Encyclopedia, 27 September 2019, 08:25 UTC, <https://en.wikipedia.org/wiki/Epilobium_brachycarpum> [accessed 2022-08-22]
• Wolff, J.-P. & Y. Krippel, 2022. Epilobium brachycarpum C. Presl (Onagraceae), une nouvelle espèce pour la flore du Luxembourg. Bulletin de la Société des naturalistes luxembourgeois 124: 3-8. [PDF 5,13 MB]

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

	False indigo-bush	Status LU: n/a. 1st record: 1934, ITW 1934.
	Buschege Schäininnech	Status Eur.: n/a. 1st record: .
	Amorphe buissonnante	RA: ISEIA: n/a Harmonia+: n/a
	Bastardindigo	Wikipedia: | Wikispecies: | CABI
	Bastaard indigostruik	Back to the list of neophytes

Brief description

Amorpha fruticosa L. originates from North America and is cultivated as an ornamental. It was introduced in Europe from France to Russia (EPPO 2022). The fast-growing, deciduous shrub grows preferentially in wetlands, like riparian and alluvial habitats, sandy banks of ravines, coastal areas, and dunes. However, it tolerates some disturbed areas, such as plantations, orchards, meadows and urban areas. Due to its high reproductive capacity, A. fruticosa can form dense thickets that outcompete native flora, change successional patterns and reduce biodiversity. It is now generally accepted to be among the most invasive alien species in Europe. Repeated cutting and mowing can help to control populations of this species (CABI 2022). 

In 2014, Switzerland added the Fabaceae to its List of Invasive Alien Plants (EPPO 2022).

Status and distribution in Luxembourg

Amorpha fruticosa L. has been recorded for the first time in Luxembourg in 1934 in Noertzange (Herbier Witry).

Risk assessment

ISEIA protocol

Not assessed yet.

Harmonia+ protocol

Not assessed yet.

Worldwide distribution

 

Bibliography

• CABI, 2019. Amorpha fruticosa. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2022-08-22]
• Wikipedia contributors, 2022. ‘Amorpha fruticosa‘, Wikipedia, The Free Encyclopedia, 9 August 2022, 01:26 UTC, <https://en.wikipedia.org/wiki/Epilobium_brachycarpum> [accessed 2022-08-22]

 Page content last updated on 2023-09-26. Last proofread by Caroline Grounds on 2022-09-06.

	Water lettuce	Status LU: absent.
	Waasserzalot	Status Eur.: established. 1st record: <1850. IAS of EU concern (2022).
	Laitue d’eau	RA: ISEIA: n/a Harmonia+: n/a
	Wassersalat	Wikipedia: | Wikispecies: | CABI
	Watersla	Back to the list of neophytes

Brief description

Pistia stratiotes L., is often called water cabbage, water lettuce, Nile cabbage, or shellflower. Its native distribution is uncertain but is probably pantropical; it was first discovered from the Nile near Lake Victoria in Africa.It is now present, either naturally or through human introduction, in nearly all tropical and subtropical fresh waterways and is considered an invasive species as well as a mosquito breeding habitat. It floats on the surface of the water, its roots hanging submersed beneath floating leaves.

Water lettuce is among the world’s most productive freshwater aquatic plants and is considered an invasive species. The species can be introduced to new areas by water dispersal, fragmentation, and hitchhiking on marine transportation or fishing equipment. The invasion of Pistia stratiotes in the ecosystem can lead to environmental and socio-economic ramifications to the community it serves. In waters with high nutrient content, particularly those that have been contaminated with human loading of sewage or fertilizers, water lettuce can exhibit weedy overgrowth. It may also become invasive in hydrologically altered systems such as flood control canals and reservoirs. The severe overgrowth of water lettuce can block gas exchange in the surface water, creating hypoxic conditions and eliminating or disrupting various native marine organisms. Blocking access to sunlight, large mats of water lettuce can shade native submerged plants and alter communities relying on these native plants as a source of food. The growth of these mats can also get tangled in boat propellers and create challenges for boaters or recreational fishermen. (Wikipedia contributors 2022).

IAS of Union concern

Pistia stratiotes was first introduced into Europe in the 19th century (Loudon et al. 1850). The first published record of its presence in the wild dates to 1973 in the water canals of the Netherlands (Mennema 1977). An historic overview is given by Živković et al. 2019.

In 2022, Pistia stratiotes L. 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

Pistia stratiotes L. 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 (13.7.2022).
  • CABI, 2010. Pistia stratiotes. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2022-08-19]
  • Loudon JC, Loudon J, Don G, Lindley J, Greville RK, 1850. Loudon’s Hortus Britannicus: A Catalogue of All the Plants Indigenous, Cultivated In, Or Introduced to Britain. Longman, Brown, Green, and Longmans, UK, 735 pp.
  • Mennema J., 1977. Is waterlettuce (Pistia stratiotes L.) becoming a new aquatic weed in the Netherlands. Natura, Netherlands 74: 187–190.
  • Wikipedia contributors, 2022. ‘Pistia stratiotes’, Wikipedia, The Free Encyclopedia, 27 September 2019, 08:25 UTC, <https://en.wikipedia.org/wiki/Pistia> [accessed 2022-08-19]
  • Živković et al., 2019. Pistia stratiotes – a new invasive alien species in Vojvodina (Serbia). BioInvasions Records 8(2): 218–229, https://doi.org/10.3391/bir.2019.8.2.03

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

	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.