| Cultivar Name | Plant Size | Origin | Flower Color | Season | Source | Registered |
| 'L'Île d'Orléans' | Medium | Unknown | Near-White | - | Bastille, Jocelyne | --NR-- |
| 'October Skies' | Large | Unknown | - | - | Bemis, Royall | --NR-- |
| 'Ogon Hime' (Sieboldii) | - | Sport | - | - | Unknown | --NR-- |
| 'Ogon Hime Tokudama' | Small | Unknown | Pale-Lavender | June into July | Unknown & Ruh, Peter | .2002 .2018 |
| 'Ogon Otome Gibosa' | Small | Unknown | - | - | Unknown | --NR-- |
| 'Ogon Tachi' | Large | Unknown | Deep-Purple | August | Lantis, Clarence & Ruh, Peter | .2002 .2018 |
| 'Oh Cindy' | Medium | Sport | Pale-Lavender | July | Benedict, Dr Ralph (Herb) | --NR-- |
| 'Oh My Darling' | Small | Unknown | - | - | Unknown | --NR-- |
| 'Old Ironsides' | Giant | Sport | Med-Lavender | July | Summers, Alex | --NR-- |
| 'Omatsu-san Nishiki' | Small | Unknown | Light-Purple | - | Ruh, Peter | .2002 .2018 |
| 'Ophir' | Medium | Unknown | Pale-Lavender | - | Fischer, Dr Ulrich | --NR-- |
| 'Orphan Train Rider' | Small | Unknown | Med-Lavender | July into August | Kwick, Charles | .2017 |
| 'Osiris Illumination' | Giant | Unknown | - | - | Fafard, Serge | --NR-- |
| 'Owens Outrage' | Medium | Unknown | Med-Lavender | - | Moore, Jeff | --NR-- |
|