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 'Purple Smoke' (Indigo weed 'Purple Smoke'): Tall spikes of violet pea-like flowers on almost black stems, attractive grey-green foliage. Dark-grey seed pods. Hardy. Up to 1.2m

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

Campanula portenschlagiana 'Resholdt's Variety' (Wall bellflower 'Resholdt's Variety'): Carpeting alpine with brilliant blue flowers over a long flowering period in summer.

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

Euphorbia characias subsp. wulfenii (Mediterranean spurge): Evergreen perennial with blue-green leaves and vibrant lime-green flowers in early summer. Prefers full sun. Hardy to about -10C, but not for long periods. Up to 1.2m.

Linum perenne 'Blau Saphir' (Syn. L. perenne 'Blue Sapphire') (Perennial flax): Slender wand like stems, topped with open faced blue flowers in summer. To 30cm. Hardy.

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 grandiflora 'Summer Magic' (PBR) (Catmint 'Summer Magic'): A more compact, upright growing variety of Catmint with aromatic grey foliage and spikes of lavender blue flowers. Hardy. Up to 35cm.

Nepeta racemosa 'Snowflake' (Catmint 'Snowflake'): Compact variety of catmint forming mounds of silvery-green foliage and masses of clear white flowers. Loved by bees. Hardy. Up to 45cm.

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 40cm. Hardy.

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.

Persicaria affinis 'Darjeeling Red' (Knotweed 'Darjeeling Red'): Semi-evergreen mat-forming perennial with green narrow leaves that turn bronze over winter. Spikes of pink poker-like flowers which darken with age.

Saxifraga x urbium (London Pride): Wiry stems topped with dainty pale pink flowers over ground evergreen rosettes of green leaves with creamy yellow markings.

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