Garden plants gone wild!

A major avenue for seed dispersal, the Dranse river is now filled with exotic plants that have escaped from gardens and been carried down by the river. Summer Lilac (1) often confused with Common Lilac (2), Canadian Goldenrod, Himalayan Balsam, Black Locust, or even Japanese Knotweed colonize the banks of the Dranse river!
For example, Japanese knotweed has shown no hesitation in spreading rapidly in patches, and even invading very large areas.

These are invasive plants, competing with local flora and harming the fauna diversity! Humans are the main cause of such invasions. Asters CEN74, administrator of the nature reserve, and SIAC, in charge of river works, are implementing various measures to limit the spread of some of these plants.