Enter the Hogweed

 I am indebted to my friend Susan in New York for alerting me to a piece in the New York Times – headlined 'A Toxic Alien is Taking Over Russia' – that contains the glorious sentence 'Enter the hogweed'. This conjures up startling images of the giant hogweed yomping over the steppe in the manner of John Wyndham's mobile, carnivorous Triffids. And indeed, when the giant hogweed started getting noticed in England around 1970, it was likened to a Triffid in many a newspaper headline. 
  'It had been growing in Britain for more than 150 years,' writes Richard Mabey in Flora Britannica, 'an awesome but apparently well-mannered curiosity of Victorian shrubberies and ornamental lakesides, with no more than a hint of troll-like mischief in its huge, looming umbels ... Then, in 1970, it broke cover.'
   I first noticed it, probably in that year, growing by the water along the Cambridge 'backs', and an impressive sight it was. The thing grows to 12ft and more, with a thick, speckled stem and cartwheel-sized flowerheads. It is not a pretty sight, though undeniably sculptural, and it is not only invasive but toxic, direct contact with the plant causing an unpleasant rash.
   Our giant hogweed, Heracleum mantegazzianum, is a different species from the Russian menace (Heracleum sosnowskyi), but they are close relatives, and all giant hogweeds are good for a little public panic from time to time, and the odd newspaper headline. 
  One of Mabey's Flora Britannica contributors writes of giant hogweed growing along the river Kent in Cumbria. 'Occasionally it escapes onto the roadside verge and causes a frisson of anxiety in the local newspapers, which describe the dangers of handling it ... When gas pipes were being laid across the A6 nearby, a warning notice, 'Danger, Heavy Plant Crossing', was displayed at the foot of one of these escapees.'