This group of perennials is so distinctive; they are sort of thistle-like, but with more refinement and and delicacy. There are several species with many cultivars, ranging in heights from 2 to 4 feet tall and about half as wide. They tend to be erect and stiff, with deeply lobed or toothed leaves, ranging from deep green to nearly whitish blue. Flowers are thistle-like, are frequently set atop showy bracts, and bloom late summer.
Grow in well drained soil in full sun; tolerates poor, sandy soils. Overly fertile soils or over-fertilizing may cause it to sprawl. This is a tap-rooted plant that transplants poorly once established and so is best left undisturbed. Plants are biennial, so in the first year, basal rosettes of foliage form that overwinter as evergreen rosettes. In the second year, plants send up flowering stems, produce flowers and seed before dying. As is the case with foxgloves (Digitalis) and hollyhocks (Alcea), these eryngiums will self-seed and remain in the garden from year to year as if they were perennial unless spent flower heads are deadheaded prior to seed drop. Stock purchased at nurseries is typically in its second year, though you may want to check.