Flowers along the sidewalk

We have had many questions about the flowers along the sidewalk.  They are a Lychnis, more commomnly called Rose campion.  ‘Alba’ are the white flowered ones.  They are biennials and last year were just short woolly, silver-gray rosettes.  This year they have grown to 24 inches so far and are flowering freely.  Our hope is that they will self seed freely.