Ceanothus

Ceanothus × delilianus 'Henri Desfosse' (Henri Desfosse Ceanothus)
Ceanothus integerrimus (Deer Brush)
Ceanothus sanguineus (Redstem Ceanothus )

Ceiba

Ceiba speciosa (Floss Silk Tree)

Cephalanthus

Cephalanthus occidentalis (Buttonbush )

Cercidiphyllum

Cercidiphyllum japonicum (Katsura )

Cercis

Cercis canadensis (Eastern Redbud)
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)

Chamaebatiaria

Chamaebatiaria millefolium (Fernbush )

Chilopsis

Chilopsis linearis (Desert Willow )

Chimonanthus

Chimonanthus praecox (Fragrant Wintersweet)

Chionanthus

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

Chitalpa

Chitalpa tashkentensis 'Pink Dawn' (Pink Dawn Chitalpa)

Chrysothamnus

Chrysothamnus viscidiflorus (Green Rabbitbrush )

Cladrastis

Cladrastis kentukea (American Yellowwood)

Clematis

Clematis (hybrid) (Hybrid Clematis)
Clematis montana var. rubens (Pink Anemone Clematis)
Clematis tangutica (Golden Clematis)
Clematis terniflora (Sweet Autumn Clematis, )
Clematis viticella (Italian Clematis)
Clematis viticella 'Huldine' (Huldine Italian Clematis )
Clematis viticella 'Polish Spirit' (Polish Spirit Italian Clematis)

Clerodendrum

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

Clethra

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

Cornus

Cornus 'Eddies White Wonder' (Eddie's White Wonder Dogwood)
Cornus Venus® (Venus Dogwood)
Cornus alba (Tatarian Dogwood )
Cornus alternifolia (Pagoda Dogwood)
Cornus amomum (Silky Dogwood)
Cornus canadensis (Bunchberry)
Cornus controversa (Giant Dogwood)
Cornus controversa 'June Snow' (June Snow Giant Dogwood)
Cornus drummondii (Rough-leaved Dogwood)
Cornus × elwinortonii Starlight® (Starlight Dogwood)
Cornus florida (Flowering Dogwood )
Cornus florida 'Golden Nugget' (Golden Nugget 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 Scarlet Fire® (Scarlet Fire Dogwood)
Cornus kousa 'Sunsplash' (Sunsplash Dogwood)
Cornus kousa 'Wolf Eyes' (Wolf Eyes Dogwood)
Cornus mas (Corneliancherry Dogwood)
Cornus nuttallii (Pacific Dogwood )
Cornus nuttallii 'Goldspot' (Goldspot Dogwood, )
Cornus officinalis (Japanese Cornelian Dogwood )
Cornus racemosa (Gray Dogwood )
Cornus × rutgersensis Celestial® (Celestial Dogwood)
Cornus sanguinea (Bloodtwig Dogwood)
Cornus sanguinea 'Midwinter Fire' (Midwinter Fire Dogwood)
Cornus sericea (Redosier Dogwood )
Cornus sericea subsp. occidentalis (Western 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)
Corylus colurna (Turkish Hazel)
Corylus cornuta var. californica (Western Hazel )

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 divaricatus (Spreading Cotoneaster)
Cotoneaster horizontalis (Rockspray Cotoneaster )
Cotoneaster intergerrimus (European Cotoneaster)
Cotoneaster lucidus (Hedge Cotoneaster)
Cotoneaster multiflorus (Many-flowered Cotoneaster)
Cotoneaster simonsii (Simons Cotoneaster)

Crataegus

Crataegus 'Autumn Glory' (Autumn Glory Hawthorn)
Crataegus ambigua (Russian Hawthorn)
Crataegus columbiana (Columbia Hawthorn)
Crataegus crus-galli (Cockspur Hawthorn)
Crataegus douglasii (Douglas Hawthorn )
Crataegus germanica (Medlar)
Crataegus laevigata (English Hawthorn )
Crataegus laevigata Crimson Cloud™ (Crimson Cloud Hawthorn)