| Cultivar Name | Plant Size | Leaf Color | Variegation | Var Color | Origin | Flower Color | Season | Source | Registered |
| 'Cabaret' | Medium | Dark-Green | Marginal | White | Sport | Med-Lavender | July into August | Hansen, Hans | --NR-- |
| 'Cabin Boy' | Medium | Light-Green | - | - | Hybrid | Light-Purple | July into August | Kwick, Charles | .2017 |
| 'Camelot' | Medium | Blue/Green | - | - | Unknown | Pale-Lavender | July | Smith, Eric & British Hosta and Hemerocallis Society | .1988 |
| 'Candle In The Dark' | Medium | Light-Green | Streaked | Yellow | Unknown | - | - | Asch, Stuart | --NR-- |
| 'Canterbury Tales' | Medium | Med-Green | Marginal | White | Sport | Med-Lavender | July into August | Malloy, Alex | .2002 |
| 'Captain America' | Large | Dark-Green | Marginal | Yellow | Hybrid | Near-White | June into July | Balitewicz, Bob | --NR-- |
| 'Captain Kirk' | Large | Blue/Green | Medial | Yellow | Sport | Pale-Lavender | July | Brill, Kirk | .1999 |
| 'Carnival' | Medium | Med-Green | Marginal | Yellow | Hybrid | Pale-Lavender | July into August | Lachman, Wm & Lachman, Eleanor | .1986 |
| 'Carolina Moon' | Medium | Med-Green | Marginal | Yellow | Sport | Pale-Lavender | July into August | Breiwick, Al | .1997 |
| 'Carousel' | Medium | Med-Green | Marginal | Yellow | Hybrid | Pale-Lavender | August | Lachman, Wm & Lachman, Eleanor | .1989 |
| 'Carrie' | - | - | - | - | Duplicate | - | - | Stone, David | --NR-- |
| 'Casablanca' | Large | Dark-Green | Marginal | White | Unknown | - | - | Janssen, Bill | --NR-- |
| 'Cassanova' | Medium | Med-Green | Streaked | Speckles | Sport | Light-Purple | August | Seaver, Charles | --NR-- |
| 'Cat in the Hat' | Giant | Med-Green | Medial | Yellow | Sport | - | - | Sisson, Kathie | --NR-- |
| 'Cat's Meow' | Medium | Med-Green | Marginal | Chartreuse | Sport | Pure-White | June into July | Falstad, C.H. | .1998 |
| 'Cavalcade' | Large | Blue/Green | Marginal | White | Hybrid | Pale-Lavender | June | Lachman, Wm & Lachman, Eleanor | .1990 |
| 'Cease Fire' | Large | Blue/Green | Marginal | White | TC Sport | Pale-Lavender | July into August | Schwarz, Jim & Schwarz, Karen & Zilis, Mark | .2014 |
| 'Centennial' | Giant | Blue/Green | - | - | Unknown | - | - | Ward, Dr Dick & Ward, Jane | .1996 |
| 'Center Stage' | Small | Med-Green | Medial | White | Unknown | Deep-Purple | July into August | Vaughn, Kevin | .1982 |
| 'Centerfold' | Large | Yellow | - | - | Unknown | Pale-Lavender | June into July | Kamp, Gayle | .1994 |
| 'Chances Are' | Giant | Blue/Green | - | - | Unknown | Near-White | June into July | Tompkins, Chet & Walek, Kevin | .2009 |
| 'Changeling' | Large | Med-Green | Marginal | Yellow | Unknown | Near-White | July into August | Pollock, Ali | .2005 |
| 'Chariots of Fire' | Medium | Light-Green | Marginal | Yellow | Hybrid | Light-Purple | August to October | Dishon, Jim | .2004 |
| 'Charlie's Angels' | Large | Yellow | - | - | Sport | Pale-Lavender | June | Zilis, Mark | .2009 |
| 'Charlotte's Web' | Small | Med-Green | Streaked | Yellow | Sport | Light-Purple | July | Beilstein, Doug & Zilis, Mark | .2009 |
| 'Cherry Bomb' | Miniature | Med-Green | Medial | White | Hybrid | Light-Purple | July | Johnson, Greg | .2004 |
| 'China Doll' | Small | Light-Green | - | - | Hybrid | Pure-White | July into August | Savory, Robert | .1988 |
| 'Chocolate Soldier' | Small | Med-Green | Marginal | Yellow | Unknown | - | - | Hawes, James | --NR-- |
| 'Chris' Flashdance' | Small | Med-Green | Streaked | White | Unknown | | | Brinkmann, Christina | --NR-- |
| 'Cinderella' | Large | Blue/Green | Marginal | Yellow | Sport | Near-White | June into July | Zilis, Mark & Schwarz, Jim | .2004 |
| 'City Boy' | Small | Med-Green | Marginal | White | Unknown | - | - | Jones, Leonard | --NR-- |
| 'City Slicker' | Medium | Dark-Green | Marginal | White | Hybrid | Deep-Purple | August to October | Dishon, Jim | .1996 |
| 'Civil War' | Large | Blue/Green | - | - | Unknown | Near-White | July | Freeman, Franc & Freeman, Sally | .2008 |
| 'Clambake' | Large | Blue/Green | - | - | Hybrid | Pale-Lavender | July into August | Goodwin, Randy | .2000 |
| 'Class Act' | Medium | Med-Green | Marginal | Yellow | Hybrid | Near-White | - | Zilis, Mark | --NR-- |
| 'Cleopatra' | Large | Med-Green | Marginal | Yellow | Unknown | Pale-Lavender | July into August | Harris, Robert | --NR-- |
| 'Cloud Nine' | Giant | Med-Green | Streaked | Yellow | Sport | Med-Lavender | July | Trucks, Gary | --NR-- |
| 'Code Red' | Small | Yellow | - | - | Unknown | - | - | Unknown | --NR-- |
| 'Colossal' | Giant | Blue/Green | - | - | Unknown | Pale-Lavender | June | Savory, Robert | .1977 |
| 'Columbus Circle' | Large | Med-Green | Marginal | Creamy White | Hybrid | Pale-Lavender | July into August | Santa Lucia, Vic & Walek, Kevin | .2009 |
| 'Command Performance' | Large | Dark-Green | Medial | White | Sport | Light-Purple | July | Janssen, Bill | --NR-- |
| 'Commander' | Large | Med-Green | Marginal | White | Hybrid | - | June into July | Zilis, Mark | .2010 |
| 'Conehead' | Small | Med-Green | - | - | Unknown | - | - | Avent, Tony | --NR-- |
| 'Continental Divide' | Large | Dark-Green | Medial | Green | Hybrid | Near-White | June into August | Groothuis, Mike & Petryszyn, Olga | .2008 |
| 'Conversation Piece' | Small | - | Streaked | - | Unknown | - | - | Aden, Paul | --NR-- |
| 'Cool Cat' | Large | Blue/Green | Streaked | Yellow | Sport | Med-Lavender | July into August | Elslager, Ed | .2005 |
| 'Cool Hand Luke' | Large | Blue/Green | Marginal | Yellow | Sport | Near-White | June into July | Naylor Creek Nursery | --NR-- |
| 'Count Dracula' | Medium | Dark-Green | - | - | Unknown | Pale-Lavender | August to September | Crockett, Clyde | .1997 |
| 'Cover Girl' | - | - | - | - | Duplicate | - | - | Duplicate Name | --NR-- |
| 'Creature from the Black Lagoon' | Medium | Dark-Green | | | Hybrid | Pure-White | July | Beistein, Doug | .2022 |
| 'Crocodile Tears' | Medium | Dark-Green | - | - | Unknown | - | - | Meyer, Bill | --NR-- |
| 'Crossroads Oscar' | Small | Med-Green | Marginal | White | Hybrid | Pale-Lavender | July | England, Tim | .2003 |
| 'Curious Yellow' (Livingston) | Small | Yellow | - | - | Unknown | Light-Purple | - | Livingston, Ron | --NR-- |
| 'Curious Yellow' (M. Seaver) | Medium | Yellow | - | - | Unknown | - | - | Seaver, Mildred | --NR-- |
| 'Curley' | Miniature | Med-Green | - | - | Sport | Med-Lavender | August | O'Brien, John | --NR-- |
| 'Curly Top' | Small | Med-Green | - | - | Hybrid | Light-Purple | August | Benedict, Dr Ralph (Herb) | .1985 |
| 'Cutting Edge' | Large | Blue/Green | - | - | Hybrid | Pale-Lavender | July into August | Benedict, Dr Ralph (Herb) & Gowen, Hideko | .1999 |
| 'Cyrus' | Giant | Dark-Green | - | - | Unknown | - | - | Wade, Van | --NR-- |
|