Sea holly (Eryngium planum ‘Blue Glitter’)

Features and Characteristics

Eryngium planum, commonly called sea holly, is a coarse, clump-forming perennial that features a summer bloom of steel-blue, thistle-like flower heads on branched stems rising from a rosette of dark green basal leaves. Basal leaves (typically elliptic to oblong, cordate-based and deeply-toothed) form a rosette to 6″ tall and to 14″ wide. Stiff, branched, violet-blue stems (to 32” tall), bearing abundant, egg-shaped, thistle-like, violet-blue flower heads, rise from each basal rosette in summer. Each flower head is a spherical-cylindrical umbel that is packed with tiny, stemless, violet-blue flowers. Each flower head is subtended by a narrow, spiky collar of spiny, blue-green bracts. Summer bloom is often profuse.

Genus name comes from an ancient Greek name used by Theophrastus for a plant which grew in Greece (probably Eryngium campestre) or is a Greek reference to the prickly or spiny nature of plants in this genus.

Specific epithet means flat.

‘Blue Glitter’ is particularly noted for producing an abundant crop of “glittering” steel blue flower heads on heavily branched stems throughout summer. Although developed at least in part for the cut flower industry, this cultivar makes an excellent addition to the home garden.