| Cultivar Name | Source | Plant Size | Leaf Color | Variegation | Var Color | Origin | Flower Color | Season | Registered |
| 'Calypso' | Lachman, Wm & Eleanor | Small | Blue/Green | Marginal | White | Hybrid | Light-Purple | July into August | .1987 |
| 'Cape Cod' | Goodenough, Rick | Medium | Blue/Green | Marginal | Yellow | Unknown | - | - | --NR-- |
| 'Cape Elizabeth Light' | Goodenough, Rick | Large | Blue/Green | Streaked | White | Unknown | - | - | --NR-- |
| 'Carnival' | Lachman, Wm & Eleanor | Medium | Med-Green | Marginal | Yellow | Hybrid | Pale-Lavender | July into August | .1986 |
| 'Carol' | Williams, Frances & AHS | Medium | Blue/Green | Marginal | White | Nat-Sport | Pale-Lavender | July into August | .1986 |
| 'Carol's Sister' | Williams, Frances | Large | Med-Green | - | - | Nat-Sport | Pale-Lavender | July into August | --NR-- |
| 'Carousel' | Lachman, Wm & Eleanor | Medium | Med-Green | Marginal | Yellow | Hybrid | Pale-Lavender | August | .1989 |
| 'Cascades' | Lachman, Wm & Eleanor | Medium | Blue/Green | Medial | White | Hybrid | Pure-White | July | .1993 |
| 'Cascades Streaked' | Lachman, Wm & Eleanor | Medium | Med-Green | Streaked | Speckles | Nat-Sport | Pure-White | July | --NR-- |
| 'Cavalcade' | Lachman, Wm & Eleanor | Large | Blue/Green | Marginal | White | Hybrid | Pale-Lavender | June | .1990 |
| 'Celebrity' | Lachman, Wm & Eleanor | Large | Blue/Green | Marginal | Yellow | Hybrid | Pale-Lavender | June into July | .1995 |
| 'Center Stage' | Vaughn, Kevin | Small | Med-Green | Medial | White | Unknown | Deep-Purple | July into August | .1982 |
| 'C'est Magnifique' | Goodenough, Rick & Gilligan, Madelon | Large | Dark-Green | Marginal | Yellow | Hybrid | Med-Lavender | July into August | .2017 |
| 'Changing Moods' | Vaughn, Kevin | Small | Yellow | - | - | Hybrid | Pale-Lavender | August to October | .1983 |
| 'Chanticleer' | Goodenough, Rick | Large | Med-Green | - | - | Hybrid | - | - | --NR-- |
| 'Chantilly Lace' | Lachman, Wm & Eleanor | Medium | Med-Green | Marginal | White | Hybrid | Pale-Lavender | August | .1988 |
| 'Charldon' | Williams, Frances | - | - | - | - | Unknown | - | - | --NR-- |
| 'Chatham Harbormaster' | Goodenough, Rick | Large | Blue/Green | Streaked | White | Hybrid | - | - | --NR-- |
| 'Chatham Lightkeeper' | Goodenough, Rick | Large | Blue/Green | Streaked | Yellow | Unknown | - | - | --NR-- |
| 'Cherry Berry' | Lachman, Wm & Eleanor | Medium | Blue/Green | Marginal | White | Hybrid | Light-Purple | July into August | .1991 |
| 'Cherry Garcia' | Herold, Roy | - | - | - | - | Unknown | - | - | --NR-- |
| 'Cherub' | Lachman, Wm & Eleanor | Miniature | Med-Green | Marginal | White | Hybrid | Pale-Lavender | July | .1989 |
| 'China Gold' | Goodenough, Rick | Large | Yellow | - | - | Hybrid | - | - | --NR-- |
| 'Chopsticks' | Herold, Roy & Walek, Kevin | Medium | Med-Green | - | - | Hybrid | Light-Purple | September to October | .2009 |
| 'Christmas Gold' | Seaver, Mildred & Walek, Kevin | Large | Yellow | - | - | Nat-Sport | Pale-Lavender | July | .2009 |
| 'Christmas Green' | Seaver, Mildred | Large | Dark-Green | - | - | Nat-Sport | Pale-Lavender | June into July | --NR-- |
| 'Christmas Tree' | Seaver, Mildred & Vaughn, Kevin | Large | Dark-Green | Marginal | White | Hybrid | Med-Lavender | June into July | .1982 |
| 'Cinnamon and Sugar' | Herold, Roy | Medium | Med-Green | - | - | Unknown | - | - | --NR-- |
| 'Cinnamon Bun' | Herold, Roy | Miniature | Med-Green | - | - | Unknown | - | - | --NR-- |
| 'Cinnamon Sticks' | Herold, Roy & Walek, Kevin | Medium | Med-Green | - | - | Hybrid | Light-Purple | August to October | .2009 |
| 'Cinnamon Twist' | Herold, Roy | Medium | Med-Green | - | - | Unknown | - | - | --NR-- |
| 'Clean Green' | Goodenough, Rick & Gilligan, Madelon | Medium | Light-Green | - | - | Hybrid | Pure-White | July into August | .2017 |
| 'Cobra' | Herold, Roy | Large | Dark-Green | - | - | Hybrid | - | - | --NR-- |
| 'Cohasset Harbormaster' | Goodenough, Rick | Large | Blue/Green | Streaked | Yellow | Hybrid | - | - | --NR-- |
| 'Confused' | Beal, R. | Medium | Med-Green | Medial | White | Nat-Sport | Pale-Lavender | July | .1999 |
| 'Constitution' | Goodenough, Rick | Medium | Dark-Green | Marginal | White | Hybrid | - | - | --NR-- |
| 'Crayons' | Seaver, Mildred | Medium | Med-Green | Streaked | White | Hybrid | Pale-Lavender | July | --NR-- |
| 'Crazier' | Herold, Roy | - | Dark-Green | Streaked | Yellow | Unknown | - | - | --NR-- |
| 'Craziest' | Herold, Roy | - | Dark-Green | Streaked | Yellow | Unknown | - | - | --NR-- |
| 'Crazy' | Herold, Roy | - | Dark-Green | Streaked | Yellow | Unknown | - | - | --NR-- |
| 'Crazy Quilt' | Lachman, Wm & Eleanor | Medium | Blue/Green | Streaked | White | Unknown | Near-White | July | --NR-- |
| 'Cream Cheese' | Lachman, Wm & Eleanor | Small | Med-Green | Marginal | Creamy White | Hybrid | Light-Purple | August to October | .1991 |
| 'Crepe Suzette' | Lachman, Wm & Eleanor | Miniature | Med-Green | Marginal | White | Hybrid | Pale-Lavender | July into August | .1986 |
| 'Crusader' | Lachman, Wm & Eleanor | Medium | Dark-Green | Marginal | White | Hybrid | Pale-Lavender | August | .1989 |
| 'Curious Yellow' | Seaver, Mildred | Medium | Yellow | - | | Unknown | | | --NR-- |
| 'Curly' | Lachman, Wm & Eleanor | Small | Blue/Green | Marginal | White | Hybrid | Light-Purple | July | .1991 |
| 'Curly Locks' | Lachman, Wm & Eleanor | Small | Med-Green | Marginal | White | Hybrid | Light-Purple | July into August | .1989 |
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