Japanese knotweed (Reynoutria japonica) in a field of lesser celandine (Ficaria verna). I'm in Pennsylvania where they were originally introduced in 1800s, both as ornamentals. The Japanese knotweed was also planted for erosion control. Now horribly invasive but at least the bees like them. #JapaneseKnotweed #LesserCelandine #InvasiveSpecies #weeds #plants #ecology #pennsylvania #pollinators #polygonaceae #ranunculaceae