Amsonia tabernaemontana (Blue dogbane): Starry blue flowers on strong stems with willowy green leaves. Hardy. Up to 90cm. [Collect Only]

Catananche caerulea (Cupid's dart): Masses of papery lavender blue flowers held on wiry stems all summer. Seed heads turn silver in late summer. Good dried flower. Up to 60cm. [Collect Only]

Catananche caerulea 'Major' (Cupid's dart 'Major'): Masses of papery blue flowers held on wiry stems all summer. Seed heads turn silver in late summer.

Eryngium bourgatii 'Picos Amethyst'': Stunning steely blue flowers on stiff stems with a gorgeous purple tint.

Eryngium bourgatii 'Picos Blue' (PBR) (Sea Holly 'Picos Blue'): Stunning steely blue flowers on blue stems. Spiny glaucous foliage. Loves sunshine and very well-drained gritty soil. Hardy. Up to 60cm.

Eryngium planum 'Blue Hobbit' (Sea Holly 'Blue Hobbit'): A more compact form with steely blue flowers on dark stems. Spiny glaucous foliage. Loves sunshine and very well-drained gritty soil. Hardy. Up to 30cm. [Collect Only]

Eryngium x zabelii 'Jos Eijking' (Sea Holly 'Jos Eijking'): Large steely blue bracts surround a dome of tiny blue flowers in summer. Long-lasting flowers.Thrives in a sunny,dry spot. To 70cm. Hardy.