Culture
Easily grown in average, consistently moist, well-drained soils in full sun. Tolerates a wide range of soils, including poor dryish ones, as long as the soils are well-drained. Plants may be grown from seed and will self-seed in the garden if not deadheaded. Deadheading the flowers will extend the bloom period, however. Once the taproot has matured, this plant is very difficult to transplant or divide without seriously damaging the taproot. Plants may be trimmed to the ground in late fall or left as is for winter interest.
Noteworthy Characteristics
Echinops sphaerocephalus, commonly known as great globe-thistle, is a bold, woolly-stemmed perennial in the thistle tribe of the composite (sunflower) family. It is native to meadows, fields, rocky brushy places and disturbed habitats in Europe and western Asia, but has been introduced in other places around the world including North America where it has naturalized over time in a number of locations in Canada from Quebec to Saskatchewan and in the U.S. from Maine to Minnesota south to Illinois, Kentucky and Virginia plus Wyoming, Colorado, Washington, Oregon and California.
Upright-branching gray stems typically rise to 3’ tall and to 2-3’ wide, but infrequently in the wild soar to as much as 4-7’ tall. Stems are clad with coarse, glandular, sinuate-pinnatifid, deeply dissected, thistle-like, green to gray-green leaves (to 14” long) which have spiny-toothed margins and white tomentose undersides. Each stem is topped in summer (late June- August) with a showy, thistle-like, spherical inflorescence (to 2” diameter) filled with lilac-white disk florets (rays absent). Fruits are hairy cylindrical achenes (1/3”) which ripen from September to October.
Genus name comes from the Greek words echinos meaning a hedgehog and ops meaning appearance in reference to the flower heads.
Specific epithet comes from the Greek words sphaera meaning round and kephalos meaning head in reference to the flower heads being of spherical shape.
‘Arctic Glow’ is an erect, clump-forming, great globe-thistle cultivar which typically grows to 3’ tall on stiff, reddish stems. It is more compact than the species. Silvery-green, slightly-spiny, deeply-dissected leaves (to 14” long) are downy-white below. Globular, thistle-like, white inflorescences (to 2-3” diameter) bloom at the stem tops in summer. White flowers contrast well with the red stems and silvery leaves.
Problems
No serious insect or disease problems. Taller stems may need staking, particularly if grown in rich, fertile soils.
Uses
Sunny borders, cottage gardens. Accent or small groups.