- Calamagrostis - Karl Foerster
- Calendula - Maayan
- Calendula officinalis - Black Centered Golden Princess
- Calendula officinalis - Black Centered Orange Princess
- Calendula officinalis - Golden Princess
- Callicarpa dichotoma - Early Amethyst
- Callistephus - Daylight Blue Frost
- Callistephus - Daylight Pink Frost
- Callistephus - Daylight Purple
- Callistephus - Daylight Red
- Callistephus - Daylight Violet
- Callistephus - Daylight White
- Callistephus - Gala Mix
- Callistephus - Hulk
- Callistephus - Meteor Mix
- Callistephus - Meteor Rose Pink
- Callistephus - Meteor Rose
- Callistephus - Serenade Blue Tipped White
- Callistephus - Serenade Carmine
- Callistephus - Serenade Light Blue
- Callistephus - Serenade Rose
- Callistephus - Serenade Rose-tipped White
- Callistephus - Serenade Scarlet
- Callistephus chinensis - Astoria Mix
- Callistephus chinensis - Giant Princess
- Callistephus chinensis - Standy’ Mix
- Callistephus Daylight Rose
- Campanula - Bernice
- Campanula - Campbell Blue
- Campanula - Champion Blue Improved
- Campanula - Champion Lavender Improved
- Campanula - Champion Light Blue
- Campanula - Champion Pink Improved
- Campanula 'Champion Pro Deep Blue'
- Campanula - Champion White Improved
- Campanula - Kent Belle
- Campanula medium - Champion Blue
- Campanula medium - Champion Pink
- Campanula persicifolia - Blue Bell
- Campanula persicifolia - White Bell
- Campanula rapunculus - Heavenly Blue
- Capsicum '10-441525'
- Capsicum '13-441552'
- Capsicum '16-441575'
- Capsicum '22-441530-2'
- Capsicum '51-59252'
- Capsicum - Cappa Round Red
- Capsicum - Cappa Topfruit White/Red
- Capsicum - Exp.
- Capsicum - Friesdorfer Orange hybrids
- Capsicum - Friesdorfer Scarlet hybrids
- Capsicum - On Top Candles Red
- Capsicum - On Top Round Bronze
- Capsicum - On Top Round Red
- Capsicum - Pumpkin on a Stick
- Capsicum - Spice Drops Scarlet Candles
- Capsicum - Spice Drops Yellow Drops
- Capsicum annuum - Chili Pepper
- Carthamus - Lasting Orange
- Carthamus - Superior Orange
- Carthamus - Yellow Grenade
- Carthamus - Yellow Grenade
- Carthamus tinctorius - Grenade Mix
- Carthamus tinctorius - Superior Orange
- Caryopteris - First Choice
- Caryopteris clandonensis - Dark Knight
- Catananche caerulea - Amor Blue
- Catananche caerulea - Amor White
- Catananche caerulea - Cupids Dart White
- Celosia: Many culltivar production trials here
- Centaurea americana - Jolly Joker
- Centaurea dealbata
- Centauridium drummondii - Flower Power
- Centranthus ruber - White
- Chasmanthium latifolium
- Chelone lyonii - Hot Lips
- Chelone obliqua
- Chrysanthemum carinatum - Merry Mixture
- Chrysanthemum parthenium - Snow
- Chrysanthemum vulgare - Gold-headed Sticks
- Cirsium japonicum - White Beauty
- Cleome - Sparkler Blush
- Cleome - Sparkler Lavender
- Cleome - Sparkler White
- Consolida - Cannes Crystal Pink
- Consolida - Cannes Deep Blue
- Consolida - Cannes Purple Picotee
- Consolida - Cannes Rose Stripe
- Consolida - Chorus Violet
- Consolida - Giant Double Dark Blue
- Consolida - Giant Orchid Blue
- Consolida - Imperial Dark Blue
- Consolida - Imperial Orchid
- Consolida - Imperial White
- Consolida - Pink Fantasies
- Consolida - Pink Perfection
- Consolida - Stiletta Indigo Blue
- Consolida - Stiletta Rosy Red
- Consolida - Super Single Imperial Orchid
- Consolida - Sydney Blue Picotee
- Consolida - Sydney Lilac
- Coreopsis 'Cerise' Year 1 Year 2
- Coreopsis 'Ruby Frost' Year 1 Year 2
- Coreopsis basalis - Gold Crown
- Coreopsis tripteris
- Cosmos - Sensation Purity Superior
- Cosmos - Tall Versailles Carmine
- Cosmos - Tall Versailles Pink Eye
- Cosmos - Tall Versailles White
- Cosmos - Tall Versailles Mixed
- Cosmos - Tickle Pink
- Cosmos - Versailles Blush Pink
- Cosmos - Versailles Pink
- Cosmos - Xanthos
- Cosmos bipinnatus - Early Wonder
- Cosmos bipinnatus - QIS Red
- Cosmos bipinnatus - QIS Rose
- Cosmos bipinnatus - QIS White
- Cosmos sulphureus - Bright Lights
- Cotinus coggygria - Young Lady
- Crocosmia - Emily McKenzie
- Crocosmia - Lucifer