Deptford pink  (Dianthus armeria)

This biennial species flowers in July and August, and is an incredibly prolific seed producer. Each plant can shed up to 400 seeds, although it is thought to need open ground for these to germinate successfully. Once established, the plant can cope with competition from taller species. Seeds disperse in late summer and a rosette of leaves grows the following year. The plant finally flowers the year after that.