Coreopsis Permathread 'Shades of Rose' is a tickseed with varying shades of pink around yellow centres.

Coreopsis Permathread 'Sweet Tart' has thread-like, bright green leaves and masses of single, raspberry pink flowers.

Cornus canadensis, or bunchberry, is an excellent native ground cover for part shade and loose humusy soils.

Cornus kousa 'Satomi' is among the best of the pink-flowered dogwoods.

Cornus mas 'Pioneer' is a cold hardy Cornelian cherry dogwood with early yellow flowers and long, pear-shaped tasty fruit.

Cornus mas 'Red Star' is a cold hardy Cornelian cherry dogwood with early yellow flowers and long, oval-shaped tasty fruit.

This Cornelian cherry, Cornus mas 'Variegata', has tiny, yellow, early spring flowers followed by gorgeous variegated foliage.

Cornus sericea (syn. stolonifera) is a beautiful native shrub known as red osier dogwood most famous for its red winter stems.

Cornus sericea 'Sunshine' offers a bright new look to the ever-popular shrubby dogwoods with its gold foliage.

Corydalis flexuosa Hillier 'Porcelain Blue' produces clusters of fragrant, glowing blue flowers atop finely textured foliage.

Corydalis solida 'Beth Evans' is an exquisite spring ephemeral with masses of pink tubular flowers. Choice.

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

Corydalis 'G.P. Baker' has amazing near-red flowers atop delicate bluish-green foliage in spring.

Corydalis solida 'Purple Bird' has warm purple flowers atop delicate bluish-green foliage in spring.

Corydalis solida 'White Knight' is an exquisite spring ephemeral with masses of pure white tubular flowers.

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.

Crassula ausensis subsp. titanopsis is a dwarf succulent with clusters of white-spotted, fleshy, leaves with pink tips sometimes flushed with pink.

Crassula capitella var. thyrsiflora, red pagoda, or shark's tooth is an amazing succulent with geometrically intriguing foliage.

Crassula capitella var. thyrsiflora 'Variegata' has clusters of geometrical foliage in shades of green, pink, and creamy yellow.

Crassula falcata is a striking succulent with large, grey, sickle-shaped leaves topped with a large cluster of fiery red flowers.