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.

Ajuga reptans (Bugle): Superb ground cover plant with purplish green leaves and blue flower spikes in summer. Very attractive to bees

Ajuga reptans 'Catlin's Giant' (Bugle 'Caitlin's Giant'): Superb ground cover plant with bronze-purple leaves and blue flower spikes in summer. Semi-evergreen. Very attractive to bees.

Ajuga reptans 'Variegata' (Bugle 'Variegata'): Superb ground cover plant with green and white variegated leaves and blue flower spikes in summer. Very attractive to bees.

Aster 'Little Carlow' (Syn. Symphyotrichum 'Little Carlow' (cordifolium hybrid)): Large sprays of small purplish blue flowers in autumn. Very reliable, easy to grow perennial. Up to 1m.

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

Brunnera macrophylla (Siberian bugloss): Heart shaped green leaves, with sprays of palest blue flowers in spring. Good in shade. Up to 30cm. [Collect Only]

Brunnera macrophylla 'Alchemy Silver' (Siberian bugloss): Large silver heart shaped leaves with dark green veining. Bright blue forget-me-not like flowers in spring. Great for shady areas. Hardy. Up to 40cm.

Brunnera macrophylla 'Alexander's Great' (PBR) (Siberian bugloss 'Alexander's Great'): Statement foliage plant for shade. Large, heart-shaped, silver leaves. Light-blue forget-me-not-like flowers in Spring. Hardy. Up to 40cm.

Brunnera macrophylla 'Hadspen Cream' (Siberian bugloss 'Hadspen Cream'): Large, heartshaped green leaves with wide cream margin. Sprays of forget-me-not blue flowers in spring. Hardy. Up to 45cm.

Brunnera macrophylla 'Jack Frost' (PBR) (Siberian bugloss 'Jack Frost'): Large, heartshaped silver leaves with green veins and leaf edges. Sprays of forget-me-not blue flowers in spring. Shade-loving plant. Hardy. Up to 45cm.

Brunnera macrophylla 'Variegata' (Siberian bugloss 'Variegata'): Large, heartshaped leaves with bold variegation. Sprays of forget-me-not blue flowers in spring. Superb shade plant. Hardy. Up to 45cm.

Campanula lactiflora 'Prichards Variety' (Milky bellflower 'Prichards Variety'): Clusters of warm blue flowers on tall stems in mid-summer. To 1m. Hardy.

Centaurea montana (Perennial cornflower): Large blue flowers in early summer, repeated later in year if cut back. Very attractive to bees. To 50cm. Hardy

Centaurea montana 'Grandiflora' (Perennial cornflower 'Grandiflora'): Larger blue flowers than the species, with darker purple heart in early summer, cut back for repeat flowering. Very attractive to bees. To 50cm. Hardy

Ceratostigma plumbaginoides (Plumbago, Hardy plumbago, dwarf plumbago): Brilliant blue flowers in later summer over foliage which turns redder as winter approaches. Stunning ground cover plant for sheltered spots. Not fully hardy in colder parts of UK. To 20cm. Frost-hardy

Cichorium intybus (Wild chicory): Large cup shaped white flowers over soft ferny foliage. Thrives in sunny, well drained spots. To 2m

Echinops bannaticus 'Blue Globe' (Globe thistle): Tall upright stems of bright blue globe flowers above clumps of spiny, grey-green leaves. Bee-friendly. Hardy. Up to 1.2m.

Echinops bannaticus 'Taplow Blue' (Globe thistle): Tall stems of pale blue globe flowers, clumps of spiny, grey-green leaves with silver undersides. Bee-friendly. Hardy. Up to 1.5m.

Eryngium alpinum 'Blue Star': Large electric-blue flowers with a spiky collar and spiky silver-green foliage. Slightly shorter then some other Eryngium varieties. Hardy. Up to 70cm. [Collect Only]

Eryngium bourgatii 'Picos Amethyst'': Stunning steely blue flowers on stiff stems with a gorgeous purple tint. Loves sunshine and well-drained soil. To 70cm. [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.

Geranium 'Alan Mayes' (Cranesbill 'Alan Mayes'): Long flowering geranium with bright blue flowers with purple veining. Clumps of hairy green leaves, turning red in autumn. Hardy. Up to 45cm.

Geranium 'Blue Cloud' (Cranesbill 'Blue Cloud'): Tall cultivar with pale blue flowers & dark purple veining above deeply divided green leaves. Long-flowering. Hardy. Up to 90cm.

Geranium 'Brookside' (Cranesbill 'Brookside'): A reliable, robust variety with large rich blue flowers over a mound of deeply divided leaves. Height to 45cm. Hardy

Geranium 'Nimbus' (Cranesbill 'Nimbus'): Makes medium sized domes of finely divided foliage smothered in purplish blue flowers in early summer. To 50cm. Hardy

Geranium 'Orion' (Cranesbill 'Orion'): A dome of deeply divided foliage, smothered in large blue flowers from early summer onwards

Geranium himalayense 'Baby Blue' (Cranesbill 'Baby Blue'): Large blue cup shaped flowers with purple veining. Spreading habit, forming a carpet of deeply divided leaves. Hardy. Up to 30cm.

Geranium himalayense 'Gravetye' (Cranesbill 'Gravetye'): Purplish blue cup shaped flowers with purple veining. Pink tinged early foliage, spreading habit

Geranium pratense 'Mrs Kendall Clark' (Meadow cranesbill 'Mrs Kendall Clark'): Palest purpley/grey flowers with beautiful veining, makes a good mound of foliage. Hardy. To 40cm.

Geranium Rozanne = 'Gerwat' (PBR) (Geranium 'Rozanne'): Noted for its large blue, white centred flowers and very long flowering period. A fine border geranium. Doesn't run. To 30cm. Hardy

Hepatica nobilis: Pretty bowl shaped blue flowers in early spring.

Nepeta 'Six Hills Giant' (Catmint 'Six Hills Giant'): A vigorous sun lover which will soon make a generous clump. Spikes of tiny purple flowers over aromatic grey/green foliage.

Nepeta racemosa 'Walker's Low' (Catmint 'Walker's Low'): Forms neat mounds of silvery green foliage, topped with masses of lavender blue flowers in early summer. Up to 60cm. Hardy.

Nepeta x faasenii (Catmint): A compact variety of catmint with mounds of aromatic silvery green foliage and lavender blue flowers.Hardy. Up to 45cm.

Nepeta x faasenii 'Purrsian Blue': A compact variety of catmint with mounds of aromatic silvery green foliage and lavender blue flowers.Hardy. Up to 45cm.

Nepeta x faassenii 'Kit Cat' (Catmint 'Kit Cat'): A compact variety of catmint making a neat mound of aromatic green foliage and clusters of lavender blue flowers. Hardy. Up to 30cm.

Phlox paniculata 'Blue Paradise' (Phlox 'Blue Paradise'): An attractive form with bright blue-purple heavily scented flowers. Good for cutting. Hardy. Up to 1.2m.

Phlox subulata 'Lilacina' (Moss phlox 'Lilacina'): Pale blue star-like flowers above a cushion of hairy narrow leaves. Good for alpine beds or rockeries. Hardy. Up to 15cm.

Polemonium Bressingham Purple = 'Polbress' (Jacob's Ladder 'Bressingham Purple'): Striking purple foliage topped with purplish blue flowers in early summer. Hardy. To 60cm [Collect Only]

Polemonium reptans 'Stairway to Heaven' (PBR) (Jacob's Ladder 'Stairway to Heaven'): Superb variety with attractive variegated foliage and lavender blue flowers. To 50cm. Hardy

Pulmonaria 'Blue Ensign' (Lungwort 'Blue Ensign'): Rich blue flowers in spring over unspotted dark green foliage. A reliable hardy perennial. Up to 30cm.

Pulmonaria 'Trevi Fountain' (Lungwort 'Trevi Fountain'): Long flowering, with blue flowers over silver-speckled leaves in spring. Great in shade. Hardy. Height to 30cm.

Salvia patens 'Cambridge Blue': Beautiful Salvia with pale blue two-lipped flowers flowering in late summer. Needs a sunny, sheltered position and protect with mulch.To 1m.

Salvia uliginosa (Bog Sage): Branched stems of clear blue flowers and lance-shaped leaves. Needs a sunny spot but with moist soil. Late flowering. To 2m.

Stokesia laevis 'Blue Star' (Stoke's aster 'Blue Star'): Large fluffy blue flowers in mid-summer, slender green leaves. To 40cm. Hardy

Stokesia laevis 'Purple Parasols' (Stoke's aster 'Purple Parasols'): Large, fluffy purple flowers over slender grey-green foliage. A lovely plant for sunny, well-drained borders. To 40cm. Hardy. [Collect Only]

Veronica austriaca 'Crater Lake Blue' (Speedwell 'Crater Lake Blue'): Vivid blue spikes above a mound of green foliage.To 30cm. Hardy.