What's sticking there? In the summer, Unter Linden can sometimes not be as cozy as usual. The culprit is a sticky rain of droplets that covers seats or parked vehicles with its annoying film. What is it exactly?
If you park under a sticky linden tree, you will get really angry
No flower nectar, but honeydew
The typical, sticky linden rain usually occurs during the flowering period of the popular park and garden tree - which is why the misconception has established itself that it is flower nectar. But the raining droplets have nothing to do with the linden blossom - they are the excretions of aphids, the so-called honeydew. The aphids appear at about the same time as the linden blossom. Incidentally, they're also very fond of populating maple trees - so parking and sitting under them can be a sticky affair from May to July, too.
So again for clarity:
- sticky rain of drops under linden trees not flower nectar but honeydew (aphid excrement)
- Also occurs under maple trees - so not specific to lime trees
What exactly is honeydew?
As I said: honeydew is aphid excretions - albeit specific ones, namely those that result from their feeding on the plant sap of the linden leaves. This consists mostly of carbohydrates and to a lesser extent of proteins. The lice mainly utilize the latter and excrete most of the carbohydrates in the form of sugar. The result is the honeydew and naturally sticky as a quasi-pure sugar juice.
Joy and sorrow of the honeydew
Honeydew critical in conjunction with fungus
Many initially only see the disadvantage of honeydew - the sticky coatings on the car or on seating furniture are of course annoying. And if the so-called sooty mold nests in it and is exposed to the sun, it can even damage the paintwork. However, honeydew is usually harmless because it is water-soluble and can easily be washed away by the next rain. The aphids are then largely washed off the leaves. The honeydew is therefore a fair weather phenomenon.
food source for bees
However, honeydew also has positive side effects - even if we can only benefit from them to a limited extent. For one thing, some beneficial insects feed on it, most notably bees. Apart from the fact that the blossoms of the linden tree are also a popular food source for the buzzing insects, the honeydew has a special meaning for (hobby) beekeepers in particular: it provides the strong, dark aroma of the forest honey.