Acting under the provincial Weed Control Act and subject to approval by the chief Ontario weed inspector, Dufferin County Council has designated giant hogweed (Heracleum Mantegassianum) as a “local,” i.e. noxious, weed in the whole of Dufferin.

The invasive plant, imported from the Orient as an ornamental circa 1900, appears only recently to have taken hold with a vengeance.

A member of the carrot family, it bears a striking resemblance to cow parsley, somewhat to Queen Anne’s Lace, and to other related weeds – except with respect to its toxicity and size.

There have been several sightings in Dufferin, and recently there appear to have been numerous ones in Toronto. CBC produced a small documentary on the growth of the weed in Renfrew County.

There have been no reports of the plant growing to a height of potentially about 20 feet, but one media photo displayed a find of about six feet in height.

The public is being warned to avoid contact with any part of the plant, and not to spend much time in its vicinity.

At best, contact could produce burning and photosensitizing of the skin within a matter of days. At worst, it could cause temporary or event permanent blindness, according to various expert Website reports.

“Giant hogweed can be a serious health hazard for humans. Its watery, clear sap contains photosensitizing compounds (furanocoumarins), which, when in contact with human skin and in combination with UV radiation, can cause burning.

“Content varies depending on plant part, but contact should be avoided at all times,” governmental website warns.

“The reaction of the skin depends on individual sensitivity. After 24 hours, reddening and swelling of the skin can be noticed, which is followed by an inflammatory reaction after three days. Depending on individual sensitivity, effects can last for months and skin can remain sensitive to UV light for years,” the report warns.

Mr. Lewis said urbanized areas would enforce control under their property standards bylaws. According to his report, all municipalities in Dufferin except Amaranth and East Garafraxa have property standards bylaws that include weeds and noxious weeds.