The balsam seems to vary in height, some of it is above my head and it must be 6ft plus.
The hogweed exceeds that by some way and can look huge! Although for the biggest part hogweed is usually juts a single plant or a few plants bunched together, unlike balsam which seems to engulf full lengths of bankings along the rive and even away from the rivers.
I remember I used to see loads of rosebay willowherb whish released clouds od seeds into the air when the seed pods opened, we called the seeds sugar stealers (don't ask me why, co's I don't know lol). As a kid I used to find lots of huge hawkmoth caterpillars on them, the caterpillars must have liked eating the leaves. I still see it but only small patches of it, no idea what knocked it back.