As part of the control of INNS (Invasive Non-native Species) we are tackling one of the lesser known INNS.
The American Skunk Cabbage AKA Swamp Lantern Lysichiton americanus is not the most attractively named species: it’s in the Arum (lily) family part of the same group as the native Lords and ladies.
This is a fairly recent addition to the INNS list; it only went on to the “ EU list of Invasive Alien Species of Union concern” in 2016 (until 2008 it was advertised as the March plant of the month on the RHS website; however now they recommend it’s not to be cultivated). Fortunately at Loch Lomond NNR we got on the case a bit more quickly than most and have been trying to eradicate this particular INNS since 2005.
A native of North Western America, its favoured habitat is shady wet woodland, swamps and stream sides. It gets its name from the putrid skunky odour of the flowers which is designed to attract flies and beetles as pollinators as they like the smell. It flowers early in the spring, later in the year producing enormous; half a metre² leaves, which completely shade out the local ground flora. In its native North America, it’s eaten by bears, freshly out of hibernation. In Scotland the absence of bears gives the Skunk Cabbage free reign over the woodland floor.
On the NNR it grows in the dark depths of Gartfairn wood; possibly one of the weirdest landscapes you’d expect to find in Scotland: it’s a primordial swamp, of deep mud, fallen willows and hidden ditches.
Gartfairn Wood; AKA the land that time forgot, Loch Lomond NNR
The immature plants resemble a Cos lettuce. This makes it quite difficult to find if it’s not flowering
Skunk Cabbage Junior
Our method of dealing with it is to dig it up by the roots (which are also quite smelly, but more akin to an onion that been left in a student’s kitchen cupboard for too long and has started to liquefy) and hang the roots in a nearby tree.
Dig Skunk Cabbage
Hung Skunk Cabbage
The bigger, tougher ones (the extensive root system can go down over 60cms beneath the surface) are given a spray of Roundup Pro bi-active. The area is then marked with tape to be checked the following year.
Metre high monster
The success of this project is that we spend a lot more time looking for them than digging them up. Whereas in other parts of the country, when left to spread, they form vast carpets
A major American skunk cabbage (Lysichiton americanus) invasion; Photo David Knott GBNNSS Website (GB Non-native species secretariat)
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.
You can get involved by reporting sightings of American skunk cabbage growing in the wild via:
Scotland’s Environment Website (no log-in required), bit.ly/SEW_INNS
Plant Tracker*, http://www.planttracker.org.uk/
* Free Apps for IoS and Android
Or you can report sightings via Scotland’s Environmental and Rural Services helpline:
telephone: 0845 2 302 050 e: email@example.com