Ophiocordyceps clavulata is a fungi parasite of scale insects feeding on trees including Pignut Hickory and American Hazel. It grows up to 4 mm
From the very limited information on the internet it's usual habitat is North America and Canada, but has also been recorded in Sweden
All photos via eol
Any corrections please post in comments and I'll edit my post
That's very interesting, thanks for sharing. Good luck with your plant!
You're welcome, and cheers ๐