A mean green actually. The only things I know about this plant are its Hungarian name (“Juliska Lapu”) and the fact that once it grows somewhere you can’t really get rid of it. I had a neighbor in Baia Sprie who actually succeeded, but used some really strong herbicide which stank up our whole street for weeks. Update on April 20, 2023 (16 years later): In the meantime I learned it’s called Japanese Knotweed / Reynoutria Japonica - https://en.wikipedia.org/wiki/Reynoutria_japonica