Hogweed creates a growing stink


From sweet as a rose to the honk of a hog!

Last week I wrote about how our lanes and waysides were abounding in sweet smelling dog roses. Well, to balance out we have nature’s evil smelling flower, the common hogweed; hogweed by name and hogweed by nature! We actually have two hogweeds – our own native Heracleum sphondylium, the common hogweed or cow parsnip, and a massive exotic one, now spreading across our region, the giant hogweed or Heracleum mantgazzianum.

This latter species was one of many Victorian introductions of spectacular plants from around the world . According to Richard Mabey for example, in 1849, seeds of this now prohibited alien were sold by Hardy & Sons of Maldon, Essex, as ‘Heracleum giganteum, one of the most magnificent plants in the world’.

By the 1870s, William Robinson, author of the Wild Garden, advocated seeding giant hogweed in rough places on the banks of rivers or artificial water, islands, or any place where bold foliage is desired. He added that ‘when established they often sow themselves, so that seeding plants in abundance may be picked up around them; but it is important not to allow them to become giant weeds’. This final statement is almost prophetic since today the plant has spread along watercourse and roadside and on derelict land. It is truly spectacular but beware the hidden danger of contact with its coarsely hairy stems or leaves – they can cause photosensitive reactions which include bad scars.

In many places, the ordinary hogweed, which can grow to two metres or so, (giant hogweed is up to four metres), is our most common member of the carrot family. Throughout July and into August this flower is abundant, though you may find flowers at almost any time of year. Where it is dominant in sheltered spots then you pick up the sometimes-overpowering smell. Indeed, hold the broad umbel of white flowers close to your nose and you will really understand why this is ‘hogweed’ – it smells of pigs. Apparently, the young stems close to the ground contain pre-emergence new flowers, which, harvested and cooked like broccoli, make succulent eating. You can see common hogweed almost anywhere but, fortunately, its giant cousin is still quite rare. However, this might be changing and if you want to see why, then get down to the River Sheaf by Heeley Baths. There is a colony here from plants which escaped from Graves Park over 20 years ago, and have washed downstream. It looks like attempts to control the hogweed have both failed and been abandoned, so now expect it down the entire Don catchment.

n Professor Ian D. Rotherham, researcher, writer and broadcaster on wildlife and environmental issues, is contactable at ianonthewildside@ukeconet.co.uk and follow ‘Ian’s Walk on the Wildside’ at www.ukeconet.org