These thick juicy heads of the young knotweed sprouts are great to cook with. You can even eat them raw. Slightly astringent, freshly acidic like Sorrell. Pick them at the end of March, beginning of April in The Netherlands This plant is originally from Asia and is considered an exotic invader in the west. As such it is seen as a plague that is dangerous and damaging to local ecology and infrastructure.
Reynoutria japonica or Fallopia japonica or Polygonum cuspidatum are the scientific names of the species. Japanse Duizenknoop is the dutch name.
photo 2020 by Willem Velthoven for Mediamatic