Some call it bachelor's buttons. I believe it is one of the centaurea's.

Centaurea cyanus, corn flower, bachelor's button?

there are.. in common parlance.. two bachelor buttons ...

the annual cornflower ...

and the perennial ...

this is the perennial

ken

ps: and this is a prime example of how.. and why ... common names can fail ....

pps: i think this is the first time.. i ever worked parlance into a sentence.. lol ...

Centaurea Montana, the perennial

It look like it might be Centaurea montana 'Mountain Bluet'. I used to have them when I lived in TN.

Thanks for the responses all, Centaurea Montana 'Mountain Bluet' seems to match this very closely.

For the nitpickers amongst us, strictly speaking Mountain Bluet should not be in inverted commas. Those are used for cultivars and Mountain Bluet is a common name rather than a cultivar. An example where you would need inverted commas would be Centaurea montana 'Purple Heart' - a cultivar name.