Pollenservice Wien

Currently there is a poplar cotton wool on the move, which can be found as white flakes in the air or on the ground. Poplar cotton wool is the seed hairs and seed threads of the poplar tree and is completely harmless. These flakes are not pollen and do not contain allergenic proteins, hence they are hypoallergenic. Poplar seed hairs and seed threads can even filter pollen from allergenic plants from the air. Poplar pollen is usually found in the air from February to early April and is no longer responsible for allergic reactions at this time of year. However, the poplar seed hairs and seed threads usually occur together with the birch or the grass pollen season and the symptoms are therefore often incorrectly attributed to the white flakes.

Photo: Flowering orchard grass (left) and flowering false oat grass (right)

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.

As weather remains unsettled, grass pollen concentrations stay low!

The grass pollen season has reached its peak flowering period. Within the city itself, orchard grass, Kentucky bluegrass, false oat grass, wall barley and brome grasses are currently in flower. In some locations, perennial ryegrass has also started to flower. In the surroundings of Vienna, the flowering of cereal crops (rye and wheat) has already begun and may intensify symptoms of grass pollen allergy.

In the meadows, dock and plantain are also flowering. Both can trigger cross-reactions in individuals allergic to grass pollen.

Oak, which can be cross-reactive to birch, is at the end of its main flowering period. Pollen allergy sufferers who are sensitized to birch pollen should still expect symptoms due to cross-reactions.

Coniferous trees such as fir, spruce, and pine are in full bloom in Vienna. In dry weather, they can release large quantities of pollen, which appears as a yellowish precipitate, known as sulphur rain, on outdoor surfaces. From an allergological point of view, however, this sulphur rain is harmless.

Nettle plants such as the stinging nettle and pellitory have also begun to flower and are releasing their first pollen.

Sunshine is possible at the beginning of the week, which means that grass pollen allergy sufferers should expect symtoms. Rain is again likely from wednesday on. Only low grass pollen concentrations are expected until the weekend. Oak will reach low pollen levels at most. Nettle plants are no issue yet.

Pollination profile

Grasses:
State of the flower: main flowering period/pollination
trend: constant
time of the start of the flower: earlier than average

Nettle plants:
State of the flower: start of flower/ hardly any pollination
trend: constant
time of the start of the flower: average

You can find the typical pollen seasons in our pollen calendar.

Tip of the season: It is advisable to wear sunglasses and headgear when going for a walk outside. These mechanical barriers ensure that your eyes and hair come into less contact with pollen, thus minimizing direct physical contact with the allergen.

Pollen spectrum:
Pollen from scorpionweeds, elderberry, mulberry, philadelphus, oilseed rape, black locust, horse chestnut, sedges, and walnut is also detected at our monitoring station.

Current main allergen: Grasses

Grass pollen allergy is the most prevalent pollen allergy in Vienna!
Pollination time in Vienna: April to September; decorative grasses extend the pollination time into autumn!

Occurrence in Vienna: The sweet grass family (Poaceae) is prevalent and found nearly everywhere. Natural monuments, parks, the banks of the Danube and obviously all areas (meadows/lawns), that are mowed infrequently, are hot spots.

Who are “the grasses“?
There are many genera and species of relevance for persons concerned, especially because reactions to different taxa of the family are individual. Those grasses, that are of highest relevance for a grass pollen allergy, are mentioned in the following.
Bluegrass (Poa pratensis): flowers from April to June. It is sowed frequently for lawns and pastures.
Orchard grass (Dactylis glomerata): flowers from May to June. It occurs frequently (especially on meadows, roadsides, ruderal areas).
Falseoat-grass (Arrhenatherum elatius): flowers from May to July. Falseoat-grass prefers pastures and clearings.
Fescue grass (Festuca sp.): flowers from May to July. This genus is species-rich and prefers marshes like fine lawns, but also alluvial forests and roadsides.
Perennial rye grass (Lolium perenne): flowers from June to July. Perennial rye grass grows frequently on meadows and pastures and is used as pasture grass.
Timothy grass (Phleum pratense): flowers from June to September. Timothy grass is an allergologically famous gras but plays a minor role in Vienna due to its infrequent distribution. It prefers natural areas.
Bermuda grass (Cynodon dactylon): flowers from July to August. Bermuda grass is a neophyte in Europa and a light and heat indicator.
Cereals (cultivated rye, wheat and maize): Cereals belong as well to the sweet grass family. Grain fields in vicinity of Vienna may cause locally increased pollination, although cereal pollen is in general larger and thus not transported as far. Cultivated rye flowers usually from May to June, wheat from June to July and maize from July to August.

Cross-reactivity to pollen of other plants: Grass pollen is highly cross-reactive among pollen of other grasses

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The first birch trees reached its readiness to flower in Vienna in the week of March 24, 2025 and went into bloom shortly afterwards (Video ©Katharina Bastl (MedUni Vienna/Pollenservice Vienna)). Accordingly, pollen release takes place under favorable conditions.

Here you can see birch catkins that are already dusting in a macro video. Pollen is released into the air as yellowish dust when touched.