Restormel Valley: Controlling Himalayan Balsam Before It Takes Hold

Finding the Balsam on the Ground

The area covered both sides of the valley and stretched for several kilometres.

Although we had been given a map, the exact locations were not marked out neatly on the ground. That meant we had to walk the site properly, search through riverbanks, field margins, woodland edges and rough vegetation, and find the balsam ourselves.

Once we found it, we removed every stem we could see.

That is the nature of Himalayan balsam control. It is not the sort of job where doing most of it is enough. If plants are missed and allowed to flower and seed, they can quickly undo a lot of the work.

Manual and Mechanical Control

Because the work was close to watercourses, we used entirely manual and mechanical methods.

No herbicide was used.

Where plants could be hand pulled, they were pulled by the roots and moved to nearby fence lines, where they were hung out to dry and die back away from wet ground. Where the balsam was too dense or widespread to pull efficiently, we used brushcutters with mulching blades to cut it below the first growth node.

Cutting below the first node is important because Himalayan balsam can regrow if it is cut too high. It is a small detail, but it is the sort of detail that decides whether the work actually controls the plant or just knocks it back for a few weeks.

The cut material was mulched and left in situ to dry out where appropriate, while pulled material was translocated carefully so it could not re-root.

Working Through the Valley

The site brought a few practical challenges.

We were working in extreme heat, across a large valley system, with dense vegetation and huge volumes of balsam in places. Some areas were easy to walk into, others needed more searching and careful movement through rough ground.

Part of the work was also close to a railway line. There were no railway-specific restrictions beyond staying within the fence boundary, which kept us safely away from the line, but it was still a constraint that the team had to remain aware of throughout the job.

We used brushcutters, mulching blades, billhooks, PPE, first aid kit and radios across the site. Because the work covered such a wide area, communication between operatives mattered. The team needed to move through the valley methodically, record where work had been completed, and make sure patches were not missed.

There were also the usual ecological considerations that come with this type of work: nesting birds, riverbank disturbance, watercourse protection and avoiding unnecessary damage to surrounding native vegetation.