Monday, June 09, 2014

Bird Cherry (Prunus padus)

Here are some photos of Bird Cherry (Punus padus) when it was newly in bloom  (I took these on April 15th 2014 in West Swindon).










The trunk is smooth and grey. It does not look very like other Cherries - it lacks those familiar horizontal bands of lenticels. The racemose cherries (like this one, and Cherry Laurel, and Portugal Laurel) are a different group.




Lovely! But sometimes the Bird Cherry is spectacular in a different way, when the whole tree (and even its surroundings) become a grey-tented nursery for caterpillars of the Bird Cherry Ermine moth (Yponomeuta evonymella). Here's what I saw today (June 9th, West Swindon). Dramatic attacks like this are said to be more common in a warm spring.




The Bird Cherry Ermine moth is known as häggspinnmal in Sweden, where Bird Cherry (hägg -  Prunus padus) is valued in the woods and as a specimen tree in gardens. So it's all the more distressing when it's transformed overnight into a skeleton hung with webs. In the Finnish lyric Kanteletar 2:150, this is the nemesis that allows the humble birch to triumph over the flamboyant bird cherry:

          Tuli toukka, tuomen kaivoi,
                Kukat kaunoset kaotti.

          maggots gnawed the bird cherry
                destroyed its fair flowers...       (trans. Keith Bosley)



When the caterpillars have finished eating everything, they cocoon together in large swagbags like this.



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By midsummer, 12 days later, things have moved on a bit. From a distance the webby trunk looks as if it's been decorated with Swan filters. These of course are the emerging moths.




They hung around, feebly fluttering onto our hands, clothes, hair and cameras, while we took useless pictures of them.








Meanwhile, the upper canopy is full of fresh new leaves. Looking skywards, the trees are almost back to normal.




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The Bird Cherry Ermine isn't usually so devastating, though that's when we're apt to notice it. Below are a couple of overheads showing a typical low-level attack. (Photos taken June 3rd, 2015)







Here's an older post about the related Spindle Ermine.

And another post about the Orchard or Cherry Ermine.



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