This grower is sure of this plant identification.
As they mature the bracts become more silver
Giant sea holly, Miss Willmott's ghost, Sea holly
Eryngium giganteum (Giant sea holly). A rosette biennial from Iran producing silver-blue thistles with heart-shaped leaves.
They are fully to half hardy. Grow in sun with fertile well drained soil.
Grown for their flowers, foliage and habit. Suitable for coastal conditions.