American skunk cabbage

Lysichiton americanus

Overview

Photo credit: ©Dick Shaw CABI
Lysichiton americanus
Common Names:
  • American skunk cabbage

Widely Spread Species:
  • Under Article 19 of Invasive Alien Species Regulation (1143/2014) American skunk cabbage has been identified as a Widely Spread Species in Northern Ireland and as such, management measures have been put in place to minimise its impacts.

Description:
  • The American skunk cabbage is a North American plant with large leathery leaves and bright yellow flowers. Its name comes from the putrid odour the flowers produce in spring. It grows in swamp forests and associated wetlands, fens, wet meadows, bogs, alluvial woodlands as well as along streams, riverbanks, lakes and ponds.
  • It is a tall herb (up to 1.5 m high, covering approximately 1m² ground) with large (40-70 cm up to 1.5 m) glossy light green leaves coming from short thick fleshy rhizomes (up to 30 cm long and 2.5-5 cm diameter). The 1 to 2 (sometimes up to 4) inflorescences are surrounded by a showy bright yellow spathe up to 45 cm high, enclosing one fleshy, up to 25 cm long spadix carrying many flowers at the bottom.
  • Flowers are small, yellowish green, often monoecious with female flowers below and male above (with generally 4, sometimes 6 stamens); bisexual flowers are also found. Flowers consist of generally 4, sometimes 6 free or fused sepals. They usually flower between March and May before leaves appear (variable dependant on location in Ireland).
  • The fruits are green berries at the end of the spadix, and mature in its natural range from June to early August (also variable regionally). Flowering and fruiting are earlier in the native range as compared to northern and central Europe (Alberternst and Nawrath, 2002).

Origin and Worldwide Distribution:
  • Its origins are from North America, and was introduced into Europe a century ago as an ornamental garden plant. Having escaped into the wild, it is now present in Belgium, Denmark, Finland, France, Germany, Ireland, the Netherlands, Sweden and the United Kingdom.

Potential or Known Impacts:
  • After some years, its huge leaves build dense layers of vegetation that exclude all light and render the water beneath devoid of life. This is especially a problem in ecologically sensitive natural areas.

How did it/could it get here?
  • This attractive plant was first introduced into Europe a century ago as an ornamental garden plant.

Is it found in Ireland or Northern Ireland?
  • Present in Ireland and Northern Ireland.
  • More details can be seen on NBDC and NBN Atlas NI.

Static Distribution Map as of December 2019 - Courtesy of CEDaR


  • Methods for Prevention:
  • In view of its potentially serious harmful impact on Natura 2000 sites, sales and any planting or keeping, including in gardens, is now banned and concerted action is required to contain its invasion and prevent its spread into other countries. As it is one of the species on the EU Species of Union Concern first list of 37 species, the UK, Ireland and EU have produced Risk Assessments (R.As.).
  • Report all sightings to CEDaR.
  • The UK R.A.
  BE PLANT WISE!

Current Legislative Position (Listed on 03 August 2016)
  • This species must not intentionally be brought into the Union; kept; bred; transported to, from or within the United Kingdom, unless for the transportation to facilities in the context of eradication; placed on the market; used or exchanged; permitted to reproduce, grown or cultivated; or released into the environment. For further queries, you can contact the Non Native Invasive Species Team in the Northern Ireland Environment Agency on 028 9056 9558.

Species Related Files:

Invasive Species Ireland

Invasive Species Ireland