I can't clearly see the seedpods, but they resemble figworts, Scrophularia?

I'm thinking this is a Rumex species. Figworts have round seeds held in distinct candelabra like layers.

yes, it looks very Rumex-y to me too, here in Europe it is native but still a pest. I had done some meadow planing for a re-greening project, and the nature conservation folks from some department had a kind of guideline demanding to spray the stocks if a certain number per square meter was reached

Agree, Rumex. Fun fact: when I was a kid (a long, long, long time ago) we called it "coffee plant", not because it was edible/drinkable, but because when we soaked the seed pods in warm water, they turned the water reddish-brown and we used it as pretend coffee.

Rumex crispus, based on replies here and a picture I found in a book. I'll get a sample and photograph it closeup.

Do these photos clinch it for rumex crispus?