Calycanthus

Calycanthus × 'Aphrodite' (Aphrodite Sweetshrub)
Calycanthus floridus (Carolina Allspice )
Calycanthus × raulstonii 'Hartlage Wine' (Hartlage Wine Sweetbush )

Camellia

Camellia japonica (Japanese Camellia)
Camellia sasanqua (Sasanqua Camellia)

Caragana

Caragana arborescens (Siberian Peashrub )
Caragana arborescens 'Lorbergii' (Lorberg Peashrub )
Caragana frutex 'Globosa' (Globe Russian Peashrub )
Caragana pygmaea (Pygmy Peashrub )

Carissa

Carissa macrocarpa (Natal Plum)

Carpenteria

Carpenteria californica (Bush Anemone)

Ceanothus

Ceanothus 'Centennial' (Centennial Ceanothus)
Ceanothus 'Concha' (Concha Ceanothus)
Ceanothus 'Dark Star' (Dark Star Ceanothus)
Ceanothus cuneatus var. rigidus 'Snowball' (Snowball Ceanothus)
Ceanothus × delilianus 'Henri Desfosse' (Henri Desfosse Ceanothus)
Ceanothus gloriosus (Point Reyes Ceanothus )
Ceanothus griseus var. horizontalis (Carmel Creeper Ceanothus)
Ceanothus griseus var. horizontalis 'Yankee Point' (Yankee Point Ceanothus)
Ceanothus impressus (Santa Barbara Ceanothus)

Cephalanthus

Cephalanthus occidentalis (Buttonbush )

Ceratonia

Ceratonia siliqua (Carob )

Cercis

Cercis canadensis 'Forest Pansy' (Forest Pansy Redbud)
Cercis canadensis 'Ruby Falls' (Ruby Falls Weeping Redbud)
Cercis canadensis var. alba (White Flowered Redbud)
Cercis canadensis var. mexicana (Mexican Redbud)
Cercis canadensis var. texensis 'Oklahoma' (Oklahoma Redbud)
Cercis chinensis (Chinese Redbud)
Cercis chinensis 'Avondale' (Avondale Chinese Redbud)
Cercis occidentalis (Western Redbud )
Cercis siliquastrum (Judus Tree )

Chaenomeles

Chaenomeles speciosa (Flowering Quince)

Chilopsis

Chilopsis linearis (Desert Willow )

Chimonanthus

Chimonanthus praecox (Fragrant Wintersweet)

Chionanthus

Chionanthus retusus (Chinese Fringetree)
Chionanthus virginicus (White Fringetree)

Choisya

Choisya × dewitteana 'Aztec Pearl' (Aztec Pearl Choisya)
Choisya ternata (Mexican Orange)
Choisya ternata 'Sundance' (Sundance Mexican Orange )

Cistus

Cistus 'Ann Palmer' (Ann Palmer Rockrose)
Cistus 'Doris Hibberson' (Doris Hibberson Rockrose)
Cistus 'Elma' (Elma Rockrose)
Cistus 'Grayswood Pink' (Grayswood Pink Rockrose)
Cistus 'Snow Fire' (Snow Fire Rockrose)
Cistus 'Victor Reiter' (Victor Reiter Rockrose)
Cistus × corbariensis (White Rockrose)
Cistus × crispatus 'Warley Rose' (Warley Rose Rockrose)
Cistus × dansereaui 'Decumbens' (Decumbens Rockrose)
Cistus × florentinus 'Fontfroide' (Fontfroide Rockrose)
Cistus ladanifer (Common Gum Rockrose)
Cistus × oblongifolius (Oblongifolius Rockrose)
Cistus × pulverulentus 'Sunset' (Sunset Rockrose)
Cistus × purpureus (Orchid Rockrose)

Clerodendrum

Clerodendrum trichotomum (Harlequin Glorybower )
Clerodendrum trichotomum 'Stargazer' (Stargazer Harlequin Glorybower)

Clethra

Clethra alnifolia (Summersweet )
Clethra alnifolia 'Ruby Spice' (Ruby Spice Summersweet )

Coleogyne

Coleogyne ramosissima (Blackbrush)

Cornus

Cornus alba (Tatarian Dogwood )
Cornus alternifolia (Pagoda Dogwood)
Cornus amomum (Silky Dogwood)
Cornus capitata (Evergreen Dogwood )
Cornus drummondii (Rough-leaved Dogwood)
Cornus florida (Flowering Dogwood )
Cornus florida 'Welchii' (Tricolor Dogwood )
Cornus kousa (Kousa Dogwood )
Cornus kousa 'Gold Star' (Gold Star Dogwood)
Cornus kousa 'Radiant Rose' (Radiant Rose Dogwood)
Cornus kousa 'Sunsplash' (Sunsplash Dogwood)
Cornus kousa 'Wolf Eyes' (Wolf Eyes Dogwood)
Cornus mas (Corneliancherry Dogwood)
Cornus officinalis (Japanese Cornelian Dogwood )
Cornus racemosa (Gray Dogwood )
Cornus sanguinea (Bloodtwig Dogwood)
Cornus sanguinea 'Midwinter Fire' (Midwinter Fire Dogwood)
Cornus sericea subsp. sericea (Redosier Dogwood)
Cornus sericea subsp. sericea 'Argenteo-marginata' (Variegated Dogwood )
Cornus sericea subsp. sericea 'Elegantissima' (Variegated Tatarian Dogwood )
Cornus sericea subsp. sericea 'Flaviramea' (Golden Twig Dogwood )
Cornus sericea subsp. sericea 'Hessei' (Siberian Dogwood )
Cornus sericea subsp. sericea Ivory Halo™ (Ivory Halo Dogwood )

Corylopsis

Corylopsis (Winterhazel)
Corylopsis pauciflora (Buttercup Winterhazel)
Corylopsis spicata (Spike Winterhazel)

Corylus

Corylus americana (American Hazel )
Corylus avellana (Hazelnut )
Corylus avellana 'Contorta' (Contorted Filbert )
Corylus avellana 'Red Dragon' (Red Dragon Hazelnut)
Corylus avellana 'Rote Zeller' (Rote Zeller Hazelnut)

Cotinus

Cotinus coggygria (Common Smoketree )
Cotinus coggygria Golden Spirit™ (Golden Spirit Smoketree)
Cotinus coggygria 'Royal Purple' (Royal Purple Smoketree)
Cotinus obovatus (American Smoketree )

Cotoneaster

Cotoneaster bullatus (Hollyberry Cotoneaster)
Cotoneaster congestus (Pyrenees Cotoneaster)
Cotoneaster divaricatus (Spreading Cotoneaster)
Cotoneaster franchetii (Franchet Cotoneaster)
Cotoneaster horizontalis (Rockspray Cotoneaster )
Cotoneaster intergerrimus (European Cotoneaster)
Cotoneaster lacteus (Parney Cotoneaster)