you might want to adjust the white balance of your camera for more accurate color?

But it looks like a Polygonum or Persicaria to me.

Persicarias fall in the "pretty weeds" category. Nice to see in the pasture, but you don't want them taking over the flower beds ... though IIRC the Europeans have ornamental varieties.

This one looks like one of the annual Persicarias aka Smartweeds. I don't think there are any garden cultivars of those in Europe. Many of the perennial Persicarias are garden-worthy and have named cultivars.