Amethyst sea holly has leathery, blue-green leaves and tall stems of round, steel-blue flowers with matching bracts. The flowers appear in mid summer and remain effective until fall.
Eryngium amethystinum is a drought-tolerant perennial that requires good drainage. It looks very striking when contrasted with the narrow foliage of ornamental grasses or the soft, round flowers of balloon flower. Also known as Blue Sea Holly or Eryngo. Hardy zones 3-9.