Notorious hay fever plant continues to spread: ‘It must be stopped’ | RTL News

Wormwood is increasingly being seen everywhere: in parks, public green areas and nature reserves. “Pollen can cause severe hay fever symptoms,” says researcher Leite de Viger from Leiden University Medical Center (LUMC).

Longest hay fever season

The Dutch Food and Consumer Product Safety Authority (NVWA) warned people last year not to remove the plant from their gardens. However, the plant was 14 percent more common in 2023 than the previous year, According to Floron’s census. The number of reports has been steadily increasing since 2015.

Alsatum ambrosia is an exotic annual plant native to North America that accidentally arrived in Europe via cargo transport. The seeds were also used as bird food. Since the beginning of this century, the plant has spread to many European countries, including the Netherlands.

According to De Viger, the strong presence of wormwood ensures that more and more hay fever patients are coming. “It is a plant that many people can be allergic to,” she says. “Wormwood blooms from mid-August to October. This makes the hay fever season longer. During this period, most other plants have already finished blooming.”

According to Chris Van Dyk of the Invasive Alien Knowledge Centre, hay fever plants grow on roadsides, construction sites, gardens and vacant lots. He says climate change is playing a significant role in the spread of the disease.

“Because we’ve had warm, dry autumns in recent years, the plant has the opportunity to produce fertile seeds,” he says. “The seeds are very germinable. They can stay good for decades if they end up in the soil.”

According to the Dutch Food and Consumer Product Safety Authority (NVWA), wormwood is not considered an invasive alien species. “As far as we know, the plant does not cause any harm to nature, so it does not fall under the European definition of an invasive alien species,” says a company spokesperson.

There are no natural enemies.

But that doesn’t reassure Van Dyck. The plant is becoming increasingly difficult to control because it produces so many seeds that birds and agricultural machinery can spread. The plant also has characteristics that make it almost impossible to control.

“What makes it a bad plant is that it prevents the germination of other plant seeds, due to a certain substance that the plant spreads in the soil, and there are no natural enemies that can prevent its growth,” he says. “Spread.” To the limit.”

Residual waste

Although wormwood is on the rise in the Netherlands, De Viger does not see an increase in the amount of wormwood pollen in the air. But according to her, this does not change the fact that the plant must be controlled. “We want to prevent the release of large amounts of pollen. To do this, the spread of the plant must be stopped as much as possible.”

According to Van Dijk, everyone in the Netherlands can contribute to the fight against hay fever. People who find the plant in their gardens are advised to remove it. “Preferably as soon as possible before it blooms,” he says. “It is important to use gloves for this. The plant can cause skin irritation.” Researcher De Vijger recommends throwing the removed plants in the waste. “That way you can be sure that it will be completely destroyed.”

Municipalities can also play a role in preventing hay fever complaints by taking a close look at where trees and plants are planted: