Hesperis - Sweet Rocket

Sweet Rocket is a biennial edible flower that readily self-seeds. Flowers are mostly pinks and whites and are known to give off a lovely scent in the evenings (Hesperis is greek and relates to the evening). Leaves can be used as greens in salads and more (for best flavour, pick leaves before the plant flowers). Other culinary and medicinal uses also possible. 

Hesperis matronalis