The giant hogweed is an invasive exotic plant that is harmful to health. To talk about it, François Lajoie, director general of the Côte-du-Sud watershed organization, sat at the microphone on Friday afternoon’s program It’s Even Better. He is responsible for the second phase of the regional offensive project against the Giant Bear Claw.
What is dangerous for humans is their sap, Mr Lajoie warns. Touching the liquid, which is colorless and odorless, can cause epidermal burns.
Mr. Lajoie says that within 24 to 48 hours of contact we notice the appearance of distinct bells, second degree burns that can leave scars.
You have to be really vigilant […]. There are people who are affected by it and have burns a few days later and do not understand where it is coming from.
What he describes as a serious problem is often wrongly attributed to swimming pool products.
Since the sap’s irritating effect on the skin is activated by natural or artificial light, he recommends that if it comes into contact, the contaminated areas should be washed and rinsed quickly, and then the suspected areas should be covered with dark clothing for 72 hours.
When this plant reaches maturity after four years, its sap is dangerous throughout its growth, adds Mr. Lajoie.
How do you recognize it?
Although it reaches 5 meters in some places, Mr. Lajoie states that it tends to only reach up to 3.5 meters in the region.
On the City of Quebec website, the page dedicated to giant hogweed describes its leaves as deeply dissected and divided into large, irregular leaflets that can be 50 to 150 cm in diameter.
The city also speaks of small white flowers, grouped in umbels of 50 to 150 rays, which can reach 20 to 50 cm in diameter.
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The giant hogweed is characterized by its “small white flowers, grouped in umbels of 50 to 150 rays, which can reach 20 to 50 cm in diameter”, we read on the Quebec City website.
Photo: Courtesy
It’s a pretty plant, agrees Mr. Lajoie. That’s why hobby growers swapped out the seeds, he says.
According to Lajoie, the giant hogweed first appeared in Europe and made its way to our side of the Atlantic Ocean about forty years ago.
There were a few of these in a garden in Quebec in 1979, he drops. In Chaudière-Appalaches we have known it since about the 2000s.
At maturity, the plant shoots up a flower stalk that grows quite tall and produces 15,000 to 20,000 seeds. It will therefore propagate an incredible number of plants, says Mr. Lajoie. Our goal is not to produce seeds.
Different strategies to get rid of it
In the Chaudière-Appalaches territory, it is possible to report its presence through the byebyeberceducaucase.com site, indicates Mr. Lajoie.
On their respective websites, Lévis and Québec also recommend calling 311 to report the presence of the plant.
In Quebec, if giant hogweed occurs on private property, current city regulations require the owner to dispose of the plant and determine the city’s location.
However, if it is discovered on community property, the City of Quebec will include the site in its community inspection program. [contre] Giant hogweed, they say.
The site continues to remind that it is important never to sow, plant, propagate or transport it.
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François Lajoie and his team are pursuing “different strategies” to eradicate giant hogweed.
Photo: Courtesy
Although giant hogweed is a tough plant, Mr. Lajoie and his team are using different strategies to eradicate it. Once reported on the byebyeberceducaucase.com website, it is torn up to 30 cm from the root to get rid of it.
If immediate uprooting is not possible, for example because the plants are difficult to access or are growing in rock, the experts rely on a longer-term strategy.
The team then notes the reports, interventions and follow-up actions so that they can come back and intervene later. [lorsque la croissance du plant sera] more advanced.
Because it is a plant with multiple growth strategies, we have developed many strategies to combat it.
According to Mr. Joy, the interventions of the nine watershed organizations in the Chaudière-Appalaches region, organized since 2018 thanks to a joint project, have reduced the colonies of giant hogweed in the area by about 50%.