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

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 x zabelii 'Big Blue (Sea Holly 'Big Blue): Large electric-blue thimble-shaped flowers with a spiky collar and silver-green foliage. Long flowering and bee-friendly. Hardy. Up to 75cm

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.