Dutch hay fever season to extend into August with rising mugwort and ragweed pollen
The peak of the grass pollen season in the Netherlands has passed, but the hay fever season is far from over. Mugwort (bijvoet) plants, which cause significant allergy symptoms, are set to begin their bloom soon, with pollen levels expected to rise sharply in the coming days, weeronline reports.
Typically, mugwort starts flowering around mid-July, though the timing can vary. In 2023, for example, the bloom began only in early August. Alongside mugwort, common ragweed (alsemambrosia) is expected to contribute to allergy problems starting mid-August.
Forecasters predict that mugwort pollen concentrations will begin to increase soon and that the peak period will start next week. This peak will likely continue through early August. By late August or early September, the mugwort pollen season is expected to end. The intensity of the pollen concentration depends on the amount of pollen produced and weather conditions during the bloom.
Despite recent dry spells, mugwort plants reportedly appear healthy. Meteorologists anticipate variable summer weather with temperatures around or slightly below average for this time of year. These conditions encourage plant growth.
Periods of significant rain will temporarily reduce pollen concentrations by cleansing the air, providing some relief for allergy sufferers. However, during prolonged dry spells, pollen levels can rise quickly again.
Following mugwort, common ragweed will become a concern. This invasive plant has been gradually spreading in the Netherlands for several years, although its pollen levels remain low for now. Ragweed pollen is highly allergenic, meaning even low concentrations can cause severe symptoms for sensitive individuals.
The plant thrives when days shorten and temperatures remain high. While sizable ragweed plants have already been spotted, its pollen is not expected to appear until mid-August.
