The Japanese knotweed is called ‘itadori’ (イタドリ, 虎杖) in Japan.
The kanji word means “tiger staff” (I wonder why)…
‘Itadori’ literally means “remove pain”…
The plant is native to Japan, China and Korea.
Due to its widespread network of rhizomes, it can be very ‘invasive’.
The flowers apparently are an important source of nectar for honeybees.
Where we live, we can see them growing in the wild at the hills.
We are fond of harvesting them as a wild seasonal edible, taking only the young asparagus-lookalike shoots.
My missus peels off the fibrous outer skin and soaks them in water for a while before cooking.
They taste somewhat sourish and go quite well with fresh salad and seafood.