Photo by Huhu Uet – Own work, CC BY 3.0

Toxic ‘Giant Hogweed’ plant spreading in Waterloo, Ont.

The City of Waterloo is warning residents that a toxic plant has been spreading in the area.

The Giant Hogweed is an invasive herb that “poses a significant threat to human health,” and is also dangerous to pets, according to a city press release.

The city said the plant has been a “recurring issue” and that it has been spotted in a number of different locations. The plant can grow up to six metres in height and has white flowers at the top.

“In these public areas, city staff have been actively monitoring/destroying the plants as part of the Giant Hogweed eradication program for the City of Waterloo,” the city said. “However, eradication is a difficult, ongoing process.”

What makes getting rid of the plants so difficult is that they produce an average of 10,000 seeds, which remain viable for a long time. Larger plants can produce more than 100,000 seeds. The city said this means new plants sprout up year after year in areas the seeds have spread to.

The plant’s sap contains toxins that can cause painful blisters. If it’s then exposed to the sun, it can cause sever burns and purple scars that can last for many years. There have been reported cases of the sap causing blindness after coming in contact with eyes, but they have not been confirmed, according to the Ontario Ministry of Natural Resources.

The City of Waterloo urged any residents to stay on official trails in wooded areas at all times and to contact the city if they find any Giant Hogweed.