| No. | Cultivar Name | Source | Plant Size | Leaf Color | Variegation | Var Color | Origin | Flower Color | Season | Registered |
|
1
| 'Oasis' (Ward) | Ward, Dr Dick & Ward, Jane | Large | Blue/Green | | | Unknown | Near-White | June to July | .2012 |
|
2
| 'Ocean Tide' | Mondt, Manfred | Large | Blue/Green | | | Hybrid | Near-White | June to July | --NR-- |
|
3
| 'Oceans Away' | Hanson, Curt | Giant | Blue/Green | | | Unknown | Unknown | June to July | --NR-- |
|
4
| 'Odina' | Wade, Van | Large | Blue/Green | | | Unknown | Unknown | Unknown | --NR-- |
|
5
| 'Og, Son of Fire' | Beilstein, Doug & Malloy, Alex | Miniature | Med-Green | Marginal | White | Hybrid | Unknown | Unknown | --NR-- |
|
6
| 'Oglala' | Wade, Van | Giant | Blue/Green | | | Unknown | Unknown | Unknown | --NR-- |
|
7
| 'Ohio Blue' | Wade, Van | Unknown | Blue/Green | | | Unknown | Unknown | Unknown | --NR-- |
|
8
| 'Ohio River' | Beilstein, Doug & Malloy, Alex | Medium | Med-Green | | | Hybrid | Unknown | Unknown | --NR-- |
|
9
| 'Ojibway' | Wade, Van | Medium | Blue/Green | | | Unknown | Unknown | Unknown | --NR-- |
|
10
| 'Old Hump Back' | Wade, Van | Large | Dark-Green | | | Hybrid | Pale-Lavender | June to July | .1999 |
|
11
| 'Old Rough House' | Wade, Van | Giant | Blue/Green | | | Unknown | Unknown | Unknown | --NR-- |
|
12
| 'Olga Gibosa' | Wade, Van | Large | Med-Green | | | Unknown | Light-Purple | July to August | --NR-- |
|
13
| 'Olga's Shiny Leaf' | Thiemann, Olga & Ruh, Peter & Ruh, Jean | Small | Dark-Green | | | Sport | Med-Lavender | Unknown | .2004 |
|
14
| 'Olive Branch' | Moldovan, Steve & Ruh, Peter & Ruh, Jean | Medium | Med-Green | Medial | Yellow | TC Sport | Pale-Lavender | July | .2008 |
|
15
| 'Omaha' | Wade, Van | Large | Blue/Green | | | Unknown | Unknown | Unknown | --NR-- |
|
16
| 'On the Border' | Beilstein, Doug | Medium | Med-Green | Marginal | White | Hybrid | Pale-Lavender | August | .2007 |
|
17
| 'One and Only' | Ward, Dr Dick & Ward, Jane | Large | Yellow | | | Hybrid | Pale-Lavender | June to July | .2015 |
|
18
| 'One Fine Day' | Ward, Dr Dick & Ward, Jane | Medium | Med-Green | Marginal | Yellow | Hybrid | Near-White | June to July | .2012 |
|
19
| 'Oneida' | Wade, Van | Medium | Med-Green | | | Unknown | Unknown | Unknown | --NR-- |
|
20
| 'Only You' | Ward, Dr Dick & Ward, Jane | Medium | Med-Green | Marginal | White | Hybrid | Unknown | Unknown | .2012 |
|
21
| 'Ontario Blue' | Wade, Van | Large | Blue/Green | | | Unknown | Unknown | Unknown | --NR-- |
|
22
| 'Open Hearted' | Wade, Van | Giant | Blue/Green | | | Unknown | Unknown | July | .1999 |
|
23
| 'Oracle' | Ward, Dr Dick & Ward, Jane | Giant | Med-Green | | | Unknown | Unknown | June to July | .2003 |
|
24
| 'Orion's Belt' | Ward, Dr Dick & Ward, Jane | Large | Blue/Green | | | Hybrid | Pale-Lavender | July | .2003 |
|
25
| 'Ottawa' | Wade, Van | Large | Med-Green | | | Unknown | Unknown | Unknown | --NR-- |
|
26
| 'Ovalwood' | Beilstein, Doug & Beilstein, Mardy | Large | Blue/Green | | | Hybrid | Near-White | July | .2012 |
|
27
| 'Over the Moon' | Ward, Dr Dick & Ward, Jane | Medium | Med-Green | Marginal | White | Hybrid | Unknown | June to July | .2010 |
|