Clematis Evison 'Tranquilite' has single, light blue flowers with white stripes, light yellow centers, and contrasting anthers.

Clematis Evison 'Tranquilite' has single, light blue flowers with white stripes, light yellow centers, and contrasting anthers.

Clematis 'Vicki' has rich pink flowers with magenta-red central bands for a striking bicolour display.

Clematis 'Vicki' has rich pink flowers with magenta-red central bands for a striking bicolour display.

Clematis 'Volunteer' has lovely lavender-pink flowers with bold magenta central bands.

Clematis 'Horn of Plenty' has huge flowers 8-10 inches wide in shades of rosy purple with reddish purple veins.

'Jackmanii' has deep purple four to six inch wide flowers in profusion. It is the classic purple in the Clematis world.

Clematis 'Louise Rowe' offers lovely single and double flowers in softest mauve and pink.

Clematis 'Mme Le Coultre' has been a classic for more than 100 years with its pure white flowers and yellow stamens.

Clematis 'Nelly Moser' is more than 100 years old and still one of the most popular of all cultivars.

Clematis 'Proteus' is a historic cultivar with double and single blooms in shades of rosy-lilac.

'Rain Dance' is a re-blooming bush clematis with glorious shades of blue with contrasting cream centres.

'Rain Dance' is a re-blooming bush Clematis with glorious shades of blue with contrasting cream centres.

'Stand By Me' is a herbaceous bush clematis with blue, bell-shaped flowers which transform into creamy thread-like seed heads.

'Stand By Me Lavender' is a herbaceous bush clematis with lavender purple, bell-shaped flowers which transform into thread-like seed heads.

'Violet Stardust' is a bush clematis with violet-blue, star-shaped flowers followed by pretty seed heads.

Clethra alnifolia 'Hummingbird' is a compact shrub with white bottlebrush flowers that are fragrant and nectar-rich.

Clethra alnifolia 'Ruby Spice' is a compact shrub with pink and white bottlebrush flowers that are fragrant and nectar-rich.

Clethra alnifolia 'Summer Sparkler' is a compact shrub with long, twisting racemes of white flowers that are fragrant and nectar-rich.

Clivia gardenii forms clumps of dark green, strap-like foliage and beautiful clusters of slender, tubular flowers with orange petals tipped with green.

Clivia miniata is one of the best and easiest of all houseplants with glowing orange flowers and attractive foliage.

Clivia miniata var. citrina has dark green, strap-like foliage and striking white to creamy yellow flowers with yellow centres.

Clivia is one of the best of all houseplants with glowing orange flowers, attractive fruit, and gorgeous foliage. This one is variably variegated.

Colchicum autumnale 'Alboplenum' is one of the most beautiful of the autumn crocus with pure white double-petaled flowers.

Colchicum autumnale 'Album' is a vigorous cultivar with vase-shaped, snow white flowers produced in profusion.