Pollenservice Wien

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Purple alder is the first of the early bloomers to release pollen. Its flowering start happens usually end of December. Currently, the catkins are firmly closed, the scales are still adjoined. (©Katharina Bastl (MedUni Vienna/Pollen Service Vienna)).

Purple alder, also Spaeth´s alder (Alnus x spaethii) is a hybridization between Japanese and Caucasian alder and copes well with lower temperatures. Thus, this tree does not have a natural distribution, but is planted by man, because it would be a suitable city tree in other aspects. Purple alder is not frequently distributed in Vienna, causing its pollination to be barely measurable. Phenologic observation is even more important to forecast its flower for the right time.
Stay tuned!

The pollen season and the fungal spore season 2026 has ended! We wish you a comfortable break and keep working.
You can continuously inform yourself here, we report what we find in the air samples and how the phenological development proceeds.

We provide this convenient overview graph to visualize pollination during the calendar year besides our pollen calendars.
You find more about this seasonal overview here.

Copyright: MedUni Vienna, www.pollenservice.wien

Figure: Pollen trap of the Pollenservice Vienna of the MedUni Vienna on the rooftop of the forensic medicine; we measure the whole year.

Mid- and long-term forecast for Vienna

This forecast gives you an overview for a longer time period so that you can improve your planning.

The air in Vienna is currently almost free of allergens!

The fungal spore season has ended. Fungal spores can now only be detected in small quantities in the air samples.  Only a few fungal spores from Cladosporium, Alternaria and Epicoccum can be observed. 

Currently there are only inorganic particles such as fine dust from heating and car exhaust fumes as well as diesel particles in the air samples.

Preview on the early bloomers:
The catkins of hazel and alder appear well visible. They are firmly closed and it will take some time until their flowering start.
The catkins of purple alder (Alnus x spaethii) shall be mentioned in particular, because they are the first ones to open: the scales are tightly adjoined (see video highlight). The flower of purple alder usually starts in the end of December.

You find the typical pollination periods in our pollen calendars. 

Of course we continue with our monitoring and will keep you updated here. 

Updated on: 5th of November 2026

• The Pollenservice Vienna is part of the University Department of Otolaryngology, Head and Neck Surgery at Medical University of Vienna.
• The collaboration with GeoSphere Austria involves comparing forecasts and exchanging pollen and weather data. 
• The Pollenservice Vienna is official partner of the Gesundheitsdienst (MA15) of the City of Vienna.