| Cultivar Name | Plant Size | Leaf Color | Variegation | Var Color | Origin | Flower Color | Season | Source | Registered |
| 'Ralph' | Large | Blue/Green | Medial | White | Unknown | Near-White | July | O'Harra, Russ | --NR-- |
| 'Rambunctious' | Giant | Blue/Green | - | - | Unknown | Near-White | July | Struhar, Bill | .2018 |
| 'Ready Eddy' | Small | Blue/Green | - | - | Unknown | - | - | Benedict, Dr Ralph (Herb) | --NR-- |
| 'Richland Blue' | Large | Blue/Green | - | - | Unknown | Near-White | June into July | Wade, Van | .2007 |
| 'Ripped' | Large | Blue/Green | - | - | Unknown | Pale-Lavender | July | Soules, Marjorie & Goodenough, Rick | --NR-- |
| 'Ripple Effect' | Small | Med-Green | Medial | White | Nat-Sport | Pale-Lavender | July into August | Walters Gardens | --NR-- |
| 'Rippled Treasure' | Medium | Med-Green | - | - | Hybrid | - | June into July | Zilis, Mark | .2010 |
| 'River City Blues' | Large | Blue/Green | - | - | Unknown | Pale-Lavender | June into July | Zilis, Mark & Ankney, Barry | .2018 |
| 'Rock of Gibralter' | Large | Blue/Green | - | - | Nat-Sport | - | June into July | Zilis, Mark | .2010 |
| 'Rock'n'Roll Heart' | Large | Blue/Green | - | - | Unknown | - | - | Port, Linda | --NR-- |
| 'Rosedale John Stratton' | Medium | Blue/Green | - | - | Hybrid | - | - | Hadrava, Jerry | .1999 |
| 'Ruffled Mouse Ears' | Miniature | Blue/Green | - | - | Nat-Sport | Med-Lavender | July | Zilis, Mark | .2011 |
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