Culture
Easily grown in dry, sandy, well-drained soils in full sun. Tolerates poor soils. Tall plants tend to sprawl, particularly if grown in overly fertile soils or in anything less than full sun. This is a taprooted plant that transplants poorly and is best left undisturbed once established. Plants do not spread and do not produce viable seed.
Noteworthy Characteristics
Eryngium is a genus of about 230 species of annuals, biennials and perennials, Some are from dry, rocky coastal areas of Europe, North Africa, Turkey, Central Asia, China and North Korea. These are tough, drought-resistant plants usually with a taproot. Others are from Mexico, Brazil, Argentina and warm-temperate regions of North America, Central America and South America. They are more water-loving and are more fibrous rooted. Cultural requirements of hybrids is dependent upon species involved in the cross. All are known for their dense central head and attractive bracts.
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.
‘Sapphire Blue’ is a sea holly cultivar that is noted for the steel blue coloration in the flowers, stems and foliage. It is a coarse, thistle-like, clump-forming plant which features basal rosettes of elliptic to oblong, cordate-based, serrate leaves (to 4” long) with smaller, spiny-lobed stem leaves. Leaves and stems are tinged with blue. Tiny, stemless, steel-blue flowers tightly packed into egg-shaped heads resembling thistles appear in profusion in summer in branched clusters at the top of stiff stems rising from the centers of the basal rosettes to 28” tall. Each flower head is subtended by a narrow, spiky collar of blue-green bracts (to 1” long). U.S. Plant Patent PP11,088 issued October 12, 1999.
Problems
No serious insect or disease problems.
Uses
Borders and beds. Effective as a single specimen or in small groupings.