The big and unfriendly giant hogweed

A Victorian garden sensation has become a sensational invasive nuisance. Contact with its toxic sap causes burns and blisters that can take months to heal

It's a monster towering up to 20ft tall, leaves spreading out like giant hands and flowers arranged in clusters the size of dinner plates. This is the giant hogweed, and the tabloids have been running alarming headlines recently, claiming an explosion in numbers of "Britain's most dangerous plant" is creating havoc as it spreads in the hot weather this summer.

In reality, the plant only spreads by seed, each plant producing up to 50,000 seeds released from late August onwards and cast into the wind or water. But the giant hogweed is undoubtedly a dangerous plant, armed with highly toxic sap and just brushing past it with bare skin is enough to cause painful skin burns, which blister when exposed to ultraviolet rays in daylight, and can take months to heal. Even years afterwards the skin remains sensitive to sunlight.