Campanula carpatica 'Blue Clips' (Tussock Bellflower)
A small, spreading, mound-forming perennial with light green, heart-shaped leaves and purple-blue flowers from late spring to early autumn. Height & Spread 30cm (1ft).
Phlox subulata 'McDaniel's Cushion'
A compact, mat-forming, evergreen perennial with linear, dark green leaves and salver-shaped, deep pink flowers in late spring and early summer. Height 10cm (4in), Spread 50cm (1.5ft).
Phlox subulata 'Purple Beauty' (Alpine Phlox)
A prostrate, mat- or mound-forming, evergreen perennial with linear, needle-like, dark green leaves and, in late spring and early summer, star-shaped, lilac-pink to light purple flowers.
Saxifraga umbrosa (London Pride)
An evergreen rosette former with spoon-shaped, waxy-edged leaves and tall airy spikes of starry white flowers with red speckling in summer. Height 30cm (1ft), Spread 1m (3ft).
Viola 'Skylark' (Victorian Viola)
A compact, mound-forming, evergreen perennial with ovate, toothed, mid- to dark green leaves and, from mid-spring to mid-autumn, veined, pale lilac-blue flowers. Height & Spread 20cm (8in).