Trinational Action Days 2026
In 2026, the Three Countries Park, together with partners from the Invasive Species Working Group, once again organised two cross-border action days to combat Himalayan balsam (Impatiens glandulifera):
(1) near Cottessen (NL) along the Geul river, in a nature reserve managed by Het Limburgs Landschap; and
(2) near Bildchen (DE) along the Tüljebach stream, under the coordination of the NABU-Naturschutzstation Aachen and the Contrat de Rivière Meuse-Aval
In Cottessen, this was the second joint action following the one in 2025; in Bildchen, it was the third action day after those held in 2024 and 2025.
Both locations are situated in the Geul river basin, which stretches across numerous political borders in the heart of the Meuse-Rhine Euregio. As Himalayan balsam spreads particularly along river courses, cross-border cooperation between upstream and downstream stakeholders along the Geul is of great importance.
Impressions from the field
Cottessen, 16/06/2026
Bildchen, 06/07/2026
In Bildchen, the first successes of the annual action days are already visible:
In 2024 (bottom left), during the first action, the clearing was covered exclusively by Himalayan balsam.
In 2026 (bottom right), the plant can only be found sporadically on the same clearing.
The 2024 action day was covered by WDR (Lokalzeit Aachen). The report (in German) can be viewed here at the beginning of the programme (2 minutes).
To completely remove Himalayan balsam from the area, annual monitoring will still need to be carried out for several more years.
Himalayan balsam is included on the European list of invasive alien species to be controlled. Invasive species pose a threat to biodiversity. Effective and sustainable management of Himalayan balsam requires systematic control measures as well as continuous field monitoring over several years. Therefore, further trinational action days will also be organised in the coming years within the framework of the Invasive Species Working Group.
