Sea Holly (Eryngium Planum ‘Jade Frost’)

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.

‘Jade Frost’ is a variegated cultivar that features showy blue-green leaves with bold creamy white margins and violet-blue flowers and flowering stem branches. In cool temperatures, the margins of new leaves emerge a showy pink before eventually turning creamy white. U.S. Plant Patent PP17,370 was issued on January 16, 2007.