| Cultivar Name | Source | Plant Size | Leaf Color | Variegation | Var Color | Origin | Flower Color | Season | Registered |
| 'Cally Atom' | Wickenden, Michael | Miniature | Blue/Green | - | - | Unknown | Pale-Lavender | July | --NR-- |
| 'Cally White' | Wickenden, Michael | Large | Dark-Green | - | - | Unknown | Near-White | July | --NR-- |
| 'Camelot' | Smith, Eric & BHHS | Medium | Blue/Green | - | - | Unknown | Pale-Lavender | July | .1988 |
| 'Camouflage' | Chatto, Beth | Medium | Med-Green | Marginal | Green | Nat-Sport | Pale-Lavender | July | --NR-- |
| 'Chameleon' (Smith) | Smith, Eric | Medium | Med-Green | - | - | Hybrid | - | - | --NR-- |
| 'Chameleon' (Unknown) | Unknown | Medium | Med-Green | Streaked | Yellow | Hybrid | Med-Lavender | July into August | --NR-- |
| 'Chelsea Babe' | Smith, Eric & BHHS | Miniature | Yellow | Marginal | Green | Nat-Sport | Pale-Lavender | July | .1988 |
| 'Chelsea Ore' | Chelsea Physic Garden | Large | Light-Green | Marginal | Green | Hybrid | Pure-White | August | .1989 |
| 'Cherry Berry 5' | Jolliffe, Thomas | | | | | Unknown | | | --NR-- |
| 'Claudia' | Grenfell, Diana & Walek, Kevin | Medium | Med-Green | - | - | Hybrid | Light-Purple | July into August | .2009 |
| 'Corryvreckan' | Black, Gwen | Medium | Blue/Green | - | - | Unknown | - | - | --NR-- |
| 'County Park' | Grounds, Roger & Hutchins, Graham | Small | Med-Green | - | - | Hybrid | Near-White | July | .1983 |
| 'Cream Delight' | Ford, Richard & Mary | Medium | Med-Green | Medial | White | Nat-Sport | Light-Purple | July | --NR-- |
| 'Cream Edger' | Lewis, Alan | Small | Yellow | - | - | Nat-Sport | Pale-Lavender | June into July | --NR-- |
| 'Crow's Feet' | Pether, Glen | Medium | Med-Green | - | - | Unknown | - | - | --NR-- |
| 'Crumples' | Grenfell, Diana | Medium | Med-Green | - | - | Hybrid | Pale-Lavender | July | .1996 |
| 'Cumulonimbus' | Roberts, Mark | Medium | Yellow-Gold | Marginal | White | Nat-Sport | Pale-Lavender | - | --NR-- |
| 'Curlew' | Smith, Eric & BHHS | Large | Blue/Green | - | - | Unknown | Pale-Lavender | August to October | .1988 |
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