Why white?

Farmergarrad

Has anyone ever seen anything like this ? It’s at the base of a hedge growing on its own 

wild edges

Interesting. It won't survive sadly but it variegation does happen to some degree in a lot of plants. If there was a good example of a leaf there I would have cut and pressed it.

https://forums.botanicalgarden.ubc.ca/threads/white-chestnut-tree.40107/