Corydalis solida 'Firebird' is the best red Corydalis, producing sweetly fragrant flowers above finely dissected, fern-like foliage.

Corydalis Blue Line 'Couriblue' produces clusters of glowing blue, honey-scented flowers on cinnamon stems atop finely textured, blue-green leaves.

Cosmos atrosanguineus has flowers that smell like dark chocolate! Resistance is futile. 'Choca Mocha' cosmos is more compact with a stronger fragrance.

Cosmos peucedanifolius 'Flamingo' is a hardy cosmos with large, 3 inch wide, pink, flowers produced in great profusion through summer atop beautifully dissected foliage.

Crinum amoenum has fragrant, white spidery flowers atop strap-like leaves.

Crinum campanulatum has tropical-looking, fragrant, amaryllis-like flowers that can be white or pink, deepening with age.

Crinum graminicola is a rare species from South Africa with huge umbels of light pink to deep pink flowers and dramatic foliage.

Crinum macowanii is a hardy species with broad, rippled, blue-green foliage and large, highly fragrant, white and pink flowers.

Crinum moorei 'Album' has fragrant, white, amaryllis-like flowers that grace this South African native in early summer.

Crinum moorei 'Album' has fragrant, white, amaryllis-like flowers that grace this South African native in early summer.

So underused but so beautiful in our summer gardens. Crinum 'Ellen Bosanquet' looks like a lovely pink amaryllis.

Crocus ancyrensis 'Golden Bunch' is among the earliest to bloom in the late winter garden with an abundance of orange-yellow flowers.

Crocus angustifolius is known as the "cloth of gold crocus" with golden orangey-yellow flowers with bold purple markings.

Crocus biflorus ssp. weldenii 'Fairy' is a beautiful cultivar with ivory white inner petals and pewter purple outer ones.

Crocus chrysanthus 'Advance' has lovely lemon yellow flowers with a purple flush on the outside.

Crocus chrysanthus 'Blue Marlin' is a delicately coloured cultivar with white to palest lavender interiors and grape purple striped petals.

Crocus chrysanthus 'Fuscotinctus' is a beautiful cultivar with deep golden yellow flowers striped with burgundy red.

Crocus chrysanthus 'Gipsy Girl' has lovely yellow to deep yellow petals with deep purple to purplish-brown feathing on the outer tepals.

Crocus chrysanthus 'Herald' has lovely yellow to deep yellow petals with deep purple reverses.

Crocus chrysanthus 'Prins Claus' is a snow crocus with large, white and purple, cup shaped flowers.

Crocus chrysanthus 'Romance' sports two colours of yellow: light, creamy yellow and rich, deep buttery yellow.

Crocus corsicus flowers are bright lilac-pink on the inside and light pink on the outside with dark purple feathering.

Crocus korolkowii has orange-yellow flowers with burgundy black bases and the outer petals flecked with burgundy.

Crocus malyi has icy white petals with yellow centres, yellow stamens, and orange pistils.