Euphorbia characias (Spurge): Evergreen perennial with blue-green leaves and lime-green flowers in early summer. Long-flowering. May self-seed. Prefers a sunny spot. [Collect Only]

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.

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.

Sedum spathulifolium 'Purpureum' (Purple stonecrop): Mat forming, fleshy purple rosettes with an attractive grey cast when young. Yellow flowers in summer.

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