Unfortunately there are a fair number of invasive species of both plants and animals in the Upper Heddon Valley.
Invasive species are non-native organisms (plant, animal, microbe) that, when introduced to a new environment, spread aggressively and cause significant harm to the local ecology, economy, or human health, often by outcompeting native species for resources or by disrupting ecosystems.
In 2005 Exmoor National Park Authority set up the ENNIS project to tackle invasive species on Exmoor. They have succeeded in significantly reducing the outbreaks of a number of the invasives. However, reduced funding and ever increasing demand has meant that that a number of outbreaks remain and risk re-establishing the larger threat.
Heddon for Nature, with the advice of Devon Wildlife Trust, has set up a project to take control of invasives in the Upper Heddon Valley into a community led operation. A group of volunteers have been trained in the safe use of pesticides and in best practice and record keeping for the control of invasive plant species, with funding from the FIPL project. Hopefully we can continue the excellent work done by ENNIS and hope to keep the worst invasive plants under tight control in our district.
In 2025 we asked people to report outbreaks of Japanese and Himalayan Knotweed and we recorded 16 active sites. The larger outbreaks were treated with a foliar spray of glycosate in mid autumn. The smaller sites were treated by injecting individual plant stems with glycosate or by wiping the leaves. We will return to all these sites in summer 2026 and continue treating yearly until all traces are gone. We hope to be able to discontinue foliar spray and treat only with stem injection once the size of the outbreaks reduces.
In 2025 we also started to tackle the small number of outbreaks of Himalayan Balsam (5 sites). This invasive can be eliminated by pulling up the plants before seed is set. Groups of local volunteers have worked on all five sites, but again we need to go back early summer 2026 and continue the work.
We intend to start to control Montbretia (Crocosmia x crocosmifolia) in 2026.