Aconitum 'Stainless Steel' (Monkshood 'Stainless Steel'): Elegant, light steely grey hooded flowers over finely divided ferny foliage. Good in shade if not too dry. Hardy. Up to 1m. [Collect Only]

Aconitum carmichaelii 'Arendsii' (Monkshood 'Arendsii'): Tall spires of hooded rich blue flowers in late summer. Attractive foliage spring to autumn. To 1.5m. Hardy. [Collect Only]

Aconitum napellus (Monkshood): Dark blue hooded flowers over finely divided foliage. This Aconitum flowers early, in late spring/early summer. Height to 1.5m. Hardy. [Collect Only]

Agastache rugosa 'Liquorice Blue' (Korean mint 'Liquorice Blue'): Spikes of warm blue lipped flowers from late June onwards. Very attractive to bees. Aromatic foliage. To 1.5m. Hardy in light soils. [Collect Only]

Amsonia hubrichtii (Hubricht's bluestar): Clumps of soft feathery green foliage and palest blue star-like flowers in late Spring. Textural plant. Attractive autumn colour. Up to 60cm. Hardy

Baptisia 'Indigo Spires' (Indigo weed 'Indigo Spires'): Spikes of violet-blue pea-like flowers with a yellow edge above a mound of grey-green foliage. Long flowering. Hardy. Up to 1.2m [Collect Only]

Baptisia australis (Indigo weed): Spires of lipped indigo flowers over olive-green foliage. Flowering height 1.2m. [Collect Only]

Baptisia australis var. minor (Dwarf blue false indigo): A compact form of Baptisia australis. Purple-blue flowers like a lupin with bright green trifoliate leaves. Prefers a sunny spot. Hardy. Up to 50cm

Cichorium intybus (Wild chicory): Beautiful cornflower-blue flowers held on tall stems in late summer. May need support. Hardy. Up to 2m.

Eryngium 'Pen Blue' (Sea Holly 'Pen Blue): Electric-blue thistle-like flowers with a spiky collar and silvery-green foliage. Long flowering and attractive to bees. Hardy. Up to 60cm.

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 '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. [Collect Only]