American Skunk Cabbage ( Lysichiton Americanus )

1. American Skunk Cabbage (LysichitonAmericanus) Calum Hislop Project Co-ordinator NE INNS

2. History and Habit • Cabbage Skunk weed, Lysichitumamericanus is native to swamps and along streams in woodlands in the north-west of North America. It is named due to its distinctive “skunky” odour that it emits when it blooms and attracts its pollinators - scavenging flies and beetles. • L. americanus flowers are produced in a spadix within an attractive cadmium yellow spathe, 30-40cm tall, sometimes referred to as ‘Swamp Lanterns’ that provide a very colourful scene, which is why they are popular in some gardens. • Following its introduction into the UK in 1901, it has escaped and become naturalized in marshy areas, especially favouring nutrient rich wet woodlands, as a result of its ability to flourish in shaded conditions • In its native habitat, L. americanus seeds are also dispersed by ingestion by squirrels and bears although this has not been observed within Europe. The seeds can remain viable for up to 6 years

4. Problems created by Skunk Cabbage • The American Skunk Cabbage is a wetland plant, colonising damp woodlands, stream sides and other ‘boggy’ habitats. • The species can grow in dense stands, out-competing and out-shading native species associated with these habitats. • The American Skunk Cabbage is a particular problem in wetland habitats which have running water to assist spread. • The following images clearly show how habitat along the River Dee are threatened by the escape of this species. • Once treated there is often a mass germination of seedlings, it is thought the plant create germination inhibition, or that conditions once the parent plant has been removed especially suits germination.

6. Management • American skunk cabbage is a non-native species management priority in Scotland. • To protect vulnerable wetlands, we need to know where it grows and find any new populations quickly. • From August 2017, garden centres are no longer permitted to sell American skunk cabbage. • Gardeners who had the plants before the ban are allowed to keep them, but must act responsibly and not allow them to grow or spread outside their garden.  • Dawyck Botanic Gardens on upper Tweed has removed the plant entirely from their collection, as a precaution.  A non-invasive alternative, the Asian skunk cabbage with white lantern-shaped flowers, is still available to buy from nurseries.

7. Spraying 18th August 2016

8. 27th October 2016

9. Contact details: Calum Hislop NE INNS calum@riverdee.org 01467 642121 07769 314130