Periwinkles in flower. From the top: Greater Periwinkle (Vinca major), Lesser Periwinkle (Vinca minor) and Intermediate Periwinkle (Vinca difformis). All have the characteristic five petalled flower; V. major is shrubby, V. minor has a low sprawling habit, V. difformis is something of a scrambler.

 The Intermediate Periwinkle is the first to flower -now in fact- followed by Greater Periwinkle in late winter and Lesser Periwinkle in early spring. All are introductions from the continent; major and minor are both recorded circa sixteenth century, difformis in the nineteenth century. All three have naturalised here and there. They don't look out of place in an English wood or hedgerow but I only see them in such locales near to houses so they are most likely garden escapes.