The aliens have landed!
This is one of the most spectacular perennials. Sea-holly is from the genus Eryngium. There are many different varieties originating primarily from grasslands and coastal areas. They have spiky silver foliage and thistle like blooms.
There is a form of Eryngium that grows wild in Southeast Asia and Latin America countries. It is used as a herb and tastes similar to cilantro. It has square spiky foliage. I threw it in my rice and beans when I was in Costa Rica actually. Very tasty.
I took a picture of this blue beauty on my walk down the street. Note the bright blue stems too. It's kind of wild, eh?
Sea-holly is nice paired with ornamental grasses. They are really adaptable to most soils and prefer full sun.