Report giant hogweed, Nature Conservancy urges about toxic species

The Nature Conservancy of Canada is urging the public to document sightings of giant hogweed, the towering green plant with large umbels of white flowers and a toxic clear sap, as the weed spreads across Canada.

It can cause third-degree burns and even permanent blindness.

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• Why we can't stop the spread of gianthogweed
• Invasive hogweedspreads in B.C.
• Hogweed creeps across Nova Scotia

Dan Kraus, a biologist with the conservancy, says the invasivespecies likely arrived in Canada in the 1940s as an ornamental plantand can now be found in the Atlantic provinces, Quebec, Ontario andB.C.

Its clear sap can cause blistering third-degree burns and evenpermanent blindness if it touches the body and is then exposed tothe sun, through a phototoxic reaction.

Kraus says there is also a concern about a loss of nativebiodiversity, as giant hogweed is an aggressive plant that can
outcompete native plants and spread -- especially when it grows nearrivers and streams and its seeds are carried downstream.

He says the conservancy is asking people to document sightings ofthe invasive plant through apps such as iNaturalist, which helpsscientists understand how the plants are spreading and identifiesareas they need to be eradicated.