| Calamagrostis acutiflora "Karl Förster" |
| Calamagrostis brachytricha |
| Calamagrostis splendens |
| Calamintha "Zenith" |
| Calamintha nepeta "Blue Cloud" |
| Calamintha nepeta ssp.nepeta |
| Callicarpa bodinieri "Profusion" |
| Caltha palustris |
| Caltha palustris alba |
| Camassia |
| Camassia, dubbel wit |
| Camellia "Guiomar de Figueroa" |
| Campanula "Kent Belle" |
| Campanula "Sarastro" |
| Campanula alliariifolia |
| Campanula carpatica |
| Campanula carpatica "Alba" |
| Campanula carpatica "Flore Plena" |
| Campanula cochleariifolia |
| Campanula fenestrellata |
| Campanula garganica |
| Campanula lactiflora "Loddon Anna" |
| Campanula lactiflora "Pritchard" |
| Campanula persicifolia "Coerulea" |
| Campanula portenschlagiana |
| Campanula poscharskyana "E.H.Frost" |
| Campanula posch. "Lisduggan Variety" |
| Campanula pulla |
| Cardamine trifolia |
| Carex buchananii |
| Carex morrowii "Variegata" |
| Carex muskingimensis "Silberstreif" |
| Carex panicea |
| Carlina acaulis ssp. Simplex |
| Caryopteris "Heavenly Blue" |
| Catananche cearulea "Major" |
| Ceanothus "Gloire de Versailles" |
| Celsia roripifolia |
| Centaurea "Caramia" |
| Centaurea macrocephala |
| Centaurea montana |
| Centaurea montana "Parham Variety" |
| Centaurea pulchra major |
| Centaurea simplicicaulus |
| Cephalanthus occidentalis |
| Cephalaria tchihatchewii |
| Cerastium biebersteinii |
| Ceratophyllum demersum |
| Ceratostigma plumbaginoides |
| Chaenomeles japonica "Sargentii" |
| Chaenorhinum orig. "Blue Dream" |
| Chaerophyllum hirsutum "Roseum" |
| Chamaecyparis "Squarrosa interm." |
| Chamaemelum nobile "Treneague" |
| Chasmanthium latifolium |
| Chelone obliqua |
| Chrysanthemum haradjanii |
| Chrysanthemum macrophyllum |
| Chrysogonum virginianum |
| Chrysosplenium alternifolium |
| Cicerbita alpina |
| Cimicifuga americana |
| Cimicifuga cordifolia "Blickfang" |
| Cimicifuga rubifolia ex "Blickfang" |
| Cimicifuga simplex |
| Cimicifuga simplex "Atropurpureum" |
| Cimicifuga simplex "Brunette" |
| Cimicifuga simplex "James Compton" |
| Cimicifuga simplex "Prichard Giant" |
| Circaea alpina |
| Cistus "Barnsley Pink" |
| Cistus "Sunset" |
| Cistus "Toos" |
| Clematis "Comtesse de Bouchaud" |
| Clematis "Duchess of Albany" |
| Clematis "Madame Jules Correvon" |
| Clematis "My Angel" |
| Clematis "Paul Farges" |
| Clematis "Pink Fantasy" |
| Clematis "Princess Diana" |
| Clematis "Rouge Cardinal" |
| Clematis "Star of India" |
| Clematis "The President" |
| Clematis florida "Sieboldii" (Bicolor) |
| Clematis heracleifolia "Wyevale" |
| Clematis integrifolia |
| Clematis integrifolia "Alba" |
| Clematis jackmanii "Caroline" |
| Clematis jackmaniin"Niobe" |
| Clematis macr. "Markham's Pink" |
| Clematis recta "Purpurea" |
| Clematis texensis "Gravetye Beauty" |
| Clematis triternata "Rubromarginata" |
| Clematis viticella "Etoile Violette" |
| Clematis viticella "Rubra" (Kermesina) |
| Clematis viticella "Walenburg" |
| Clematis x jouiniana "Praecox" |
| Codonopsis clematidea |
| Coreopsis grandiflora "Sonnenkind" |
| Coreopsis lanceolata |
| Coreopsis lanceolata "Sterntaler" |
| Coreopsis rosea "American Dream" |
| Coreopsis tripteris |
| Coreopsis verticillata "Moonbeam" |
| Coreopsis verticillata "Zagreb" |
| Cornus canadensis |
| Cornus mas |
| Corydalis elata |
| Corydalis flexuosa "China Blue" |
| Corydalis flexuosa "Purple Leaf" |
| Corydalis lutea |
| Corydalis solida |
| Corylopsis pauciflora |
| Corylopsis spicata |
| Cosmos atrosanguineus |
| Cotinus coggygria "Royal Purple" |
| Crassula recurva |
| Crassula setulosa |
| Crocosmia "Emily McKenzie" |
| Crocosmia "Lucifer" |
| Crocosmia "Star of the East" |
| Crocosmia masoniorum |
| Cyclamen coum |
| Cyclamen hederifolium "Perlenteppich" |