Ipheion uniflorum is sometimes called Spring Starflower. This humble little bulb isn't much used though it's widely available in autumn. It seems to like cascading over things, perhaps that is its habit in its native range of Argentina and Uruguay?

The flowers vary from pure white to shades flushed with blue.

 

 I achieved the cascading effect (by accident it has to be said) when I planted a handful of bulbs in an old oil drum. Here I. uniflorum tumbles out of a mass of self seeded Herb Robert. The taller stems are Camassia leichtlinii coming into flower.