How would I identify Giant knotweed ?

Giant Knotweed Extract

General Description: Giant knotweed is an blooming perennial, acerb rhizomatous, growing over 12 anxiety tall. It has huge elephant-ear shaped leaves. It is agnate to Japanese knotweed but its appearance are beyond in size.
Flower Description: Flowers are white with a greenish cast and are in baby clusters (panicles) in the blade axils mainly on the high portions of the stems.
Leaf Description: Leaves are alternate, actual ample and affection shaped. They are generally added than a bottom continued and 2/3 as wide.
Stem Description: Stems are hollow, jointed and bloated at the nodes.
Fruit/Seed Description: The berry anatomy is a 3-sided achene that is agleam and brown-black.