Flower Friday - Weed!

I've no idea what this weed is, but it's rather beautiful when it's in flower.

It grows at the very edge of our gravel drive, up against the side of the house. For neatness we've tried to get rid of it by pulling it up (its stems are very thin and fragile) and by poisoning it with weedkiller but it's made of strong stuff and always comes back. So we've decided to be content with just keeping it in check and enjoying its flowers :)

Thanks as always to BikerBear for running this challenge.