Sea Holly 'Big Blue'

Eryngium planum 'Big Blue' is a superb perennial thistle, often grown as a biennial for its intense colour and striking architectural form in UK gardens. While technically a perennial, it's short-lived and often performs best when treated as a biennial, especially from seed. It produces a basal rosette of leaves, and in its second year, sends up a profusion of metallic-blue stems, topped with equally vibrant, thimble-shaped, steely-blue flower heads surrounded by spiky, iridescent bracts. These appear from mid-summer into early autumn. Fully hardy (H5) and drought-tolerant, it thrives in full sun and poor to moderately fertile, well-drained soil. Excellent for dry borders, coastal gardens, and arrangements.

Sun: Full sun.

Soil: Well-drained, poor to moderately fertile.

Hardiness: H5 — down to −15°C.

Flowering: Jul, Aug, Sep.