Common Name: sea holly
Type: Herbaceous perennial
Family: Apiaceae
Zone: 5 to 9
Height: 1.50 to 2.00 feet
Spread: 1.50 to 2.00 feet
Bloom Time: June to August
Bloom Description: Violet blue flowers and bracts
Sun: Full sun
Water: Dry
Maintenance: Low
Flower: Good Cut, Good Dried
Leaf: Colorful
Tolerate: Rabbit, Dry Soil
Culture
Easily grown in dry, sandy, poor to moderately fertile, well-drained soils in full sun. Intensity of flower and bract colors is best in areas with full sun and cool nights. Tolerates poor soils. Tolerates drought. Tall plants tend to sprawl, particularly if grown in moist fertile soils or in anything less than full sun. Deadhead flowers after bloom to retain good plant appearance. This is a taprooted plant that transplants poorly and is best left undisturbed once established.
'Big Blue’ is a patented plant that does not produce viable seed.
Noteworthy Characteristics
Eryngium x zabelii, commonly called sea holly, Zabel sea holly or eryngo, is a hybrid cross between E. alpinum and E. bourgatii. This is a coarse, stiffly-branched, taprooted, thistle-like, semi-evergreen, clump-forming hybrid (to 18-24” tall) which features showy blue to violet flowers and bracts, with some blue coloration often appearing in the stems and upper leaves. Flowers bloom early to mid-summer (June-August). Tiny blue flowers are packed into spherical-cylindrical, thistle-like, egg-shaped heads (to 2” long), each of which is subtended by a showy spiky collar of narrow blue bracts (each to 2 1/2” long). The spiny-margined, heart-shaped, basal leaves (3-5” long) and the much smaller, spiny-lobed upper stem leaves are for the most part green.
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.
Hybrid name of zabelii honors Hermann Zabel (1832-1912), German botanist.
‘Big Blue’ is an upright-columnar, thick-stemmed cultivar that is best noted for its showy, intensely-iridescent, violet blue flowers and bracts. It's the result of a chance open pollination which occurred in a controlled outdoor nursery environment in Preston, Lancashire, United Kingdom in June of 1997 between an unnamed male and an unnamed female selection of E. x zabelii. Flowers bloom throughout summer. Unique blue color extends into the stems and upper stem leaves as the flowers mature. U.S. Plant Patent PP20,636 was issued January 12, 2010.
Problems
No serious insect or disease problems.
Uses
Borders and beds. Effective as a single specimen or in small groupings of at least 3-6 plants or massed. Dry, sun-baked beds.