Usually Yellow archangel (Lamiastrum galeobdolon) is found in hedgerows or damp woodlands as here.  It is closely related to red- and white-deadnettles and apparently takes its name from the Archangel Michael as it flowers near the day dedicated to him in April and the shape of its leaves are thought to resemble the wings of an archangel.
The Celtic communities saw this plant as a guardian against evil spirits and the disease known as elf-shot which affected cattle. It was believed that elves acting on behalf of witches would fire arrows with Neolithic like flint heads at the cattle which would then cause paralysis. This was known as ‘elf stroke’. The word ‘stroke’ is all too familiar in medicine throughout the ages and the definition has remained similar over time. As with the other dead nettles they have been used in European folk medicine for centuries.
Thanks to Mtranda for the wildflower challenge