Thank you for the suggestion. We grow betony (Stachys officinalis) in the bed devoted to plants used in medieval magic here at The Cloisters, as it was credited with apotropaic powers in addition to its considerable reputation as a medicinal plant. I didn’t have it on the list I’ve compiled of plants associated with rites performed on Midsummer Eve and Day, but will look into it. If you have any specific information about the folk use of betony or any other plant associated with the solstice, I’d be very pleased if you would share it.