Radio Canada – Félix Morrissette-Beaulieu
People with pollen allergies and Quebec’s healthcare system are in for a difficult time when ragweed season arrives. This weed could affect millions more people in the coming years. As August begins, the unwanted weed is in full bloom and releasing pollen, causing irritation for those who are allergic to it. With climate change and rising atmospheric CO2 levels, laboratory tests are quite clear: ragweed will produce more and more pollen, warns biologist and Laval University professor Claude Lavoie. He estimates that the number of people affected by pollen in North America, as well as in Europe where the plant was introduced, will increase significantly. In Europe, it is estimated that the number of people affected by ragweed pollen will rise from 30 million to 70 million by 2050, the biologist adds.
You can imagine the health problem this could create.
-Claude Lavoie, biologist and professor at Université Laval
According to the Government of Quebec, ragweed is the leading cause of season allergic rhinitis across northeastern North America and is believed to account for approximately 75% of pollen allergies, affecting about 1 to 10 Quebecers. The Quebec Lung Association estimates that the costs associated with ragweed for the healthcare system range between $ 157 million to $ 240 million.
Identifying Ragweed
Unlike poison ivy, which has leaves composed of three pointed leaflets, ragweed has thin, grayish-green leaves with deeply lobed edges. According to horticulturist Larry Hodgson, it resembles a carrot leaf. It is often taller than poison ivy. Its green or reddish stem is covered with fine hairs. Ragweed has an average height of 70 cm, but can grow up to 1.5 or 2 meters, depending on where it grows. Ragweed needs only sunlight to survive and is therefore commonly found in open, unshaded areas. It is frequenly seen along streets and sidewalks, highways, vacant lots, construction sites, and industrial areas, among other places. “It needs open sapce,” Hodgson explains.
How to get rid of it ?
Completely getting rid of the weed isn’t easy, according to the horticulturist. The plant can survive and regrow for up to 40 years. First, the plant is easy to pull up, explains Larry Hodgson. Mowing the lawn will cut off the top of the plant, and it won’t be able to produce flowers, he adds. Obviously, to prevent it, you need to fill that space with other things, like grass or clover, concludes the gardening expert. It’s also possible to cover the ground with inert materials like mulch or wood chips. The Quebec Observatory on Climate Change Adaptation examined the actions taken by Quebec municipalities regarding ragweed control. Its study of 262 municipalities reveals that 50% of them use at least one ragweed prevention method. In Quebec City, the organization Craque-Bitume, with its ragweed brigade, carries out a large part of the work. Since 2018, the brigade has pulled up more than 50,000 plants.