By Gareth Meadows, Seasonal Project Officer – written in autumn 2024, with an update by Elise Cox in autumn 2025
On a late summer evening in Galcantray, looking to the south of the River Nairn, a thin vein of pink can be seen slicing through the green fields of Clydesdales and cattle that inhabit the area. From a hidden source somewhere high on the hillside, the vein can be traced ducking and weaving its way down the hill, alongside a farm, through stands of trees, under the road, and finally into the river.
This annual display of flowering Himalayan balsam stands as a memorial to a pond long since filled in where the original seeds were planted decades ago. Spreading the way balsam is wont to do, it didn’t take long for seeds to find the pond outflow, slowly colonise the burn it fed into and, from here, spread into the River Nairn.
A bit of background
Around 2015, during the long, hazy summer days, a man called John Parrot was working on an invasive species control project on the River Nairn. As part of this project he traced Himalayan balsam to what he believed was its source in the upper catchment. Working with local estates, who had Japanese knotweed and giant hogweed control programs already underway, efforts began to clear Himalayan balsam along the Nairn – although, unfortunately, these efforts could not be maintained and sustained over the years.
In 2018, invasive plant control in the Findhorn, Nairn and Lossie catchments was taken on by the Scottish Invasive Species Initiative, working in partnership with the Findhorn, Nairn and Lossie Rivers Trust. In the Nairn catchment, the Initiative began working with Green Hive, a local community and environmental charity, to tackle giant hogweed and Japanese knotweed around Nairn town as part of a wider control programme across the catchment.
Green Hive were also keen to tackle Himalayan balsam around Nairn town, particularly along the riverside park areas. This was an accessible area for volunteers to get involved and we were happy to support these efforts in the brief window of time between the giant hogweed and Japanese knotweed control seasons. The project team cleared large sections with brush cutters while volunteers pulled and stacked the plants. Green Hive regulars have continued to focus efforts on areas around Nairn to limit seed dispersal and prevent the plant spreading further in the town and parks.
However, control like this at the bottom of catchments will not eradicate the infestation or solve the problem. In the Scottish Invasive Species Initiative project we want to implement catchment wide control – starting at the upstream source and working our way steadily downstream. This ensures that cleared sites are not reinfested with seeds or materials from upstream and, in the long term, allows us to work towards catchment wide eradication. To make that approach reality, we needed to look again and identify the source of Himalayan balsam in the Nairn catchment.
Re-finding the Source of the Nile Balsam
In late August of 2024 we were driving the back roads of Galcantray channelling our inner Livingstons. My passenger Caroline was trying to follow the path of the seeding balsam and trace its route through the hills. We were delighted to see that the various maps and notes (from John Parrot and rivers trust colleagues) matched the situation on the ground. At the top of a false summit on the hillside road, we rounded a corner to see a scrubby vein of balsam that stopped abruptly at a stand of trees. Rejoice! Before us was the source of Himalayan balsam on the River Nairn – confirming where work must begin the following year.
A new hope for 2025
The Livingstone-esque expedition confirmed the source of balsam on the Nairn – essential information for the Initiative’s work going forward. Annual plant surveys from Elise Cox, John Parrots initial balsam surveys work, and Bob Laughton’s knowledge of previous projects all paved the way!
Our wee adventure stands as a great example of building on previous work and highlights the importance of communication and collaboration between different organisations. With Green Hive continuing to control Himalayan balsam on the lower Nairn and with landowners’ progress on their beats, the Scottish Invasive Species Initiative can make a fresh start on the source at Galcantray in 2025, joining these efforts together to tackle this highly invasive plant from source to sea.
2025: An update from Elise
After identifying the source of the balsam late in the season in 2024, we returned to the site in 2025 to begin control. Balsam on the site grows in a narrow strip along a shallow ditch, which runs along the edges of surrounding fields and gardens until it reaches the main stem of the River Nairn, just over a kilometre away. However, we set ourselves the task of clearing a more modest distance of just over 200m. Although the area covered by the balsam was relatively narrow, we soon discovered that it grew in and among thickets of brambles – terrain which slowed our progress considerably.
Focusing on a shorter, manageable section allowed the team to meticulously pull or cut as many plants as possible, working on either side of the shallow ditch that runs through the site. Due to its shallow root system and the dry ground from previous weeks of minimal rainfall, the plants put up little resistance to the crack team of volunteers who arrived to help their local project officer on the day. We were delighted that Gareth, who now works for the RSPB, could also join us. Most of the balsam was pulled out by hand and stacked to dry, but where the undergrowth was particularly thick, weed whackers were used to help cut paths, allowing us to reach balsam growing right in the middle of the thorny tangles.
By the end of the day, we had reached the large patch of rosebay willowherb which marked the end of our 200m stretch. Beyond it, the winking pink flowers still swayed in the breeze, but behind us the only evidence that balsam had been there at all were the neat and tidy piles of pulled plants we had left behind. While seedpods were beginning to form, none were ripe enough to begin popping. However, before leaving, we conducted a biosecurity check, cleaning out boots and shaking out folds in clothing to make sure there was no risk of accidentally transporting any seeds off site.
Now that the source has been identified and work has begun, we will continue to work on clearing balsam from the site in the coming years.
