Easily recognised by their ruff of spiky bracts surrounding a prominent, cone-like centre of tiny flowers, sea hollies make a bold statement in a sunny border or gravel garden. This variety is also known as 'Miss Willmott's Ghost', after the nineteenth-century gardener, Ellen Willmott, who liked to secretly scatter seeds of the plant in other people's gardens. The name could equally apply to the plant's appearance, with its ruff of large, prickly, steely-grey bracts that shine a ghostly silver in the sun. The marbled, heart-shaped foliage is attractive too, and shown off to best effect planted in gravel. Or try this eryngium in bold clumps among grasses. Eryngiums are also perfect for use in dried flower arrangements. This variety is biennial, but self-seeds freely.