This is Motherwort (Leonurus cardiaca). Gerard's Herball of 1597 states that "It joys to be among rubbish, in stony and other rough places, especially about Oxford".
 It grows happily in part sun/shade in the garden but Gerard's description suggests that it spread as weeds/wildflowers are prone to do on the margins of human habitation.
 As I noted in my earlier entries on Lungwort (3rd. March) and Nipplewort (4th. June) the word "wort" in the common name of a plant indicates that it was once perceived to have a medicinal use. In some cases this may be purely notional. Both of these names for example probably date back to the medieval "Doctrine of Signatures" i.e. if a plant resembles a part of the human body it was thought there would be a corresponding medicinal effect.
 Then again there are plants like Motherwort that seem to have a long history as a herbal remedy, in this case for nerve and heart conditions generally and female health in particular.
 I don't have a scientific or medical background to assess herbalism as a practice but I'm intrigued by the social and cultural history of plants as much as with botany and horticulture.
 Also I like growing plants for bees and Motherwort is a noted bee plant!