One of the Eryngium speicies, with violet blue thistle-like flowers and grey-green leaves with a tinge of purple. A striking addition to a perennial border. Grows about 24 to 36 inches tall and half as wide. Tolerates drier soils than other sea holly.
Grow in well drained soil in full sun; tolerates poor sandy soils. Over-fertile soil or over fertilizing may cause plant 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.