| No. | Cultivar Name | Leaf Color | Variegation | Var Color | Origin | Flower Color | Season | Source | Registered |
|
1
| 'Oberland Spring Air' | Med-Green | Medial | White | Sport | Pure-White | July into August | Rank, Stefan | .2013 |
|
2
| 'Ogon Sudare' | Yellow | - | - | Unknown | Pale-Lavender | July | Unknown & Ruh, Peter | .2002 .2018 |
|
3
| 'Ohh! Blue Otto' | Blue/Green | - | - | Unknown | - | - | Schulz, Ed | .2009 |
|
4
| 'Ohh! Ludell' | Yellow | - | - | Unknown | - | - | Schulz, Ed | .2009 |
|
5
| 'Ohh! Powder River Blue' | Blue/Green | | - | Unknown | Near-White | June into July | Schulz, Ed | .2020 |
|
6
| 'Okazaki' | Med-Green | - | - | Hybrid | Med-Lavender | August to September | Sugita, Hajime & Ruh, Peter & Ruh, Jean | .2002 |
|
7
| 'Okobaji' | Blue/Green | - | - | Unknown | - | - | Tompkins, Chet & Ruh, Peter & Ruh, Jean | .2008 |
|
8
| 'Orange Slices' | Yellow | - | - | TC Sport | Pale-Lavender | July into August | Zilis, Mark | .2003 |
|
9
| 'Over the Rainbow' | Med-Green | Streaked | Speckles | Hybrid | Near-White | June into July | Elslager, Ed | .2005 |
|