Its the same spectacle every year: Berlins streets are flooded with some weird cotton pollen just as the summer starts kicking in. When a light breeze brushes through the streets – the fluffy white clouds spread out and one could be lead to believe that its started snowing. Almost. But what exactly is that white cotton stuff which is so prone to flying in your eyes and mouth when you’re cycling (or walking) through Berlin?
Well first things first: Its not pollen! They are seeds from the Populus tree (Pappeln in German) – otherwise known as Poplar, Aspen and Cottonwood (all different trees but they are the same species), and quite a few streets and parks in Berlin are lined with them. In fact, Berlins got over 10,000 of them – thats almost 3% of all trees in Berlin and each one of these trees produces up to 28 million seeds. At the beginning of the summer when it gets warmer in the city, the trees jettison the seeds en masse sending them through the air creating a mass phenomenon which is known in German as „Pappelschnee“ or „Sommerschnee“ – Poplar Snow or Summer Snow.
Allergists often misattribute their pollen allergy to the white cotton floating through the air, but its actually the grass pollen which is triggered by the heat at the same time which makes their life unbearable. As innocent as the poplar seeds seem to be, they tend to be highly flammable – often catching fire when a passerby carelessly throws out his cigarette (In Geman: Link and Link). They don’t just burn though – poplar “cotton” is smoother than silk and makes for an excellent (albeit pricey) pillow and comforter filling.
As quickly as the white cotton seeds appear do they disappear again. The Aspen/Poplar/Cottonwood trees only bloom for 2 weeks, and whats left of the Poplar Snow is washed down the drain by Berlins summer storms. The more you know.