Invasive Non Native Plants (INNPS)


Invasive non native plants include species such as Himalayan Balsam, Japanese Knotweed and Rhododendron. These plants were originally brought to the UK as ornamental plants for gardens but have since spread rapidly.  Such plants are damaging to river ecosystems as they can out compete native species for sunlight and cause bank erosion. At present there are relatively few non native plant species in Sutherland, however small patches of Himalayan Balsam and Japanese Knotweed are spread throughout the area, and larger sections of Rhododendron are present on some estates.


Himalyayan Balsam, Japanese Knotweed, Skunk Cabbage and Giant rhubarb.


The Trust is actively involved in removing Non-native Invasive Plant Species from around the area. Each year Himalayan Balsam is removed from the area with the gratefully received help of volunteers.  This is done by pulling up the plants from the roots by hand.  Japanese Knotweed, Skunk Cabbage and Giant Rhubarb are treated using Glycophosphate weedkiller. Many of the stands are small but this is an ideal time to start treating and trying to eradicate these plants. This work is undertaken as part of the Scottish Invasive Species Initiative.


invasive plants2  


 Himalayan Balsam  /  Japanese Knotweed  /  Skunk Cabbage



Let us know if you see any plants - the more eyes the better!


Rhododendrons at Allt Horn (K.Batchelor)
Rhododendrons at Allt Horn (K.Batchelor)



Rhododendron ponticum is a highly invasive non native plant that spreads rapidly to the detriment of native woodland species. Often having been planted in gardens, R. ponticum will spread quickly from the main seed sources changing the look of the landscape and out competing smaller species under the main canopy. If found close to water bodies, Rhododendron can potentially affect the structure of riparian plants thus interfering with shading and fish cover.


The Trust was involved in mapping the density and distribution of Rhododendron on the Reay Forest Estate using GIS. This information is being utilised to develop removal plans to restore the habitat. Lever and mulch and stem injection are the recommended methods to successfully remove Rhododendron and prevent regrowth. 


Much work has been undertaken by Reay Forest Estate to start the eradicaion of Rhodedendron around the Estate and this is welcomed within the Trust. While it will be a long, and costly, operation, it is hoped that the recovery of the land will bring benefits to many species including salmonids.





Rhododendrons at Allt Horn (K.Batchelor)
Email :    Tel : 01971 502259 
Postal Address : WSFT, Gardeners Cottage, Scourie, By Lairg. Sutherland, IV27 4SX.
Charity number : SC024426  Useful Links
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