For the second year in a row, the Interreg Aurora funded project BB Alien and the project partner County Administrative Board hires a consultant to combat garden lupines with hot water in the Riekkola Välivaara harbour area near Haparanda. Riekkola – Välivaara is a recreation area in northeastern Sweden, near the Finnish border. The area consists of a nature reserve that borders a cottage area and a small private harbour.
Combating invasive species
Among the alien species within the area, garden lupine and himalayan balsam are the most bountiful and invasive, since the area is rocky and not suitable for digging, the project are fighting the lupines with hot water, to boil away both leaves and stems. The treatment has taken place five times in 2025 and five times in 2026. The hope is that the entire plant will die, including root systems and also trigger germination of the seed bank in the ground.
Results?
The entire harbour area and surrounding forests and bushes are visually scanned for signs of invasive plants, with a focus on garden lupine. Observed lupines are then sprayed with orange water-based spray paint to easily identify where hot water treatment is needed. In parallel, observed himalayan balsam is picked by hand due to their shallow root system and is easily plucked from the ground. Picked plants are then put in plastic bags for destruction.
The effects of the treatment
After five rounds this year, the project BB Alien can see that during the later sessions, the area has consisted primarily of smaller plants—presumably seeds triggered by increased sun exposure from plant removal following hot-water treatment and favourable weather conditions.
Learn more about the project BB Alien
