I was hoping that one of you learned gardeners might be able to name this pretty grass for me.

The plant stands around 3 foot high, and has long thin leaves like a grass, but it's burst into fronds of lovely powder blue flowers.

I've taken a photo of the flowers, but the picture doesn't show the pale blue coloring very well, or the dark purplish center of the bloom. The flowers don't appear to have a scent.

Here it is: