Geograph - photograph every grid square

Heracleum mantegazzianum is a spectacular giant species of hogweed, like its smaller cousin the common hogweed but bigger in all respects, growing up to about 2 metres in height. An alien species, introduced into parks and gardens in the 19th Century as an ornamental plant but it is highly invasive and has spread throughout the whole of Great Britain, particularly along riverbanks. It is also poisonous; the sap is notorious for causing skin blisters in sunny weather (although this is also a feature of common hogweed sap). Contact with the eyes can cause permanent blindness. Giant Hogweed is difficult to eradicate; this plant always seems to survive despite extensive control measures.

This is part of an infestation along the bank of the River Irwell below Hinds Lane. Notices nearby (SD7909 : Danger! Giant Hogweed) warn of its dangers and advise:
“DO NOT TOUCH ANY PART OF THE PLANT”