"Emery Davis" wrote
Yup, Eryngium. I grow it in a border, that's what it looks like very
early in the year, except mine is a bit thicker by now. Lovely plant.

Yes, probably Eryngium planum - tall stems with sprays of spiky blue
flowerheads that individually are smaller than some other eryngium
flowers, but you get masses of them. I had a really good deep blue form
from Bressingham once that I regret losing. It was very showy.

--
Sue