For tree lovers there are two enormous, venerable, beautiful Caucasian Wingnuts in a tiny park next to the Amstel on Plantage Parklaan in Amsterdam.
They have 10-inch catkins of pale green flowers in summer, and their seeds are collectible in autumn, where they fall next to a glass memorial to the Jews killed in WW2. Some of the seedlings are now growing in Lancashire.
Conveniently, over the road is the Botanical Garden, with a Shagbark Hickory as fine as any you are likely to see in Europe.
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