I'm frequently asked what this plant is by visitors to the garden during the neighbourhood's annual Open Gardens weekend in May. Needless to say the event has been cancelled this year but the plant has made its usual entrance.
 I'm surprised this species isn't more used in gardens given how reliable and attractive it is. The Latin name is Melittis melissophyllum but it has a curious common name: Bastard Balm. There seems to be considerable variation in colour, including a white form and a much paler variation of the ones I have in the garden.
 It is said to be a wild plant of ancient woods and old hedgerows in South West England but it must be rare. I have never seen it on any of my rambles in that part of the world.