Daisies.

These tiny flowers are a variety of Erigeron, they are about the size of a little finger nail. A couple of years ago we bought a ready planted hanging basket it contained one of these plants. It produced masses of flowers.
They self seeded into a large pot and survived last winter, in spring we cut off the damaged ends of the plant and they have flowered all summer, now they have seeded and flowered all round our back door area.