| Cultivar Name | Plant Size | Origin | Flower Color | Season | Source | Registered |
| 'I Bluit' | Medium | Unknown | Pale-Lavender | July into August | Benedict, Dr Ralph (Herb) & Benedict, Dorothy & Kuenster, Rod | .2010 |
| 'Ice Palace' | Medium | Hybrid | Near-White | June | Ward, Dr Dick & Ward, Jane | .2003 |
| 'Ice Prancer' | Large | Hybrid | Pale-Lavender | July | Sawyer, Rick | --NR-- |
| 'I'm So Blue' | Large | Unknown | Near-White | June | Schwarz, Jim | .1999 |
| 'I'm So Pretty' | Large | Sport | Pale-Lavender | July | Schwarz, Jim | .2003 |
| 'Incredible Hunk' | Giant | Unknown | Pale-Lavender | July | Elslager, Ed | .1998 |
| 'Indian Princess' | Large | Hybrid | Near-White | June | Harshbarger, Gretchen & Ruh, Peter | .1998 |
| 'Indiana Blue' | Medium | Unknown | Pale-Lavender | July into August | Balitewicz, Bob | --NR-- |
| 'Indianapolis Blue' | Large | Hybrid | Near-White | June into July | Wade, Van | .2007 |
| 'Indigo' | Medium | Hybrid | Near-White | July | Savory, Robert | .1984 |
| 'Infatuation' | Medium | Hybrid | Deep-Purple | August to September | Solberg, Robert | .2016 .2018 |
| 'Interstate 71' | Large | Sport | Pale-Lavender | June into July | Beilstein, Doug & Zilis, Mark | .2009 |
| 'Irische See' | Medium | Hybrid | Pale-Lavender | July | Klose, Heinz & Ruh, Peter | .1998 |
| 'Irish Cream' | Large | Sport | Med-Lavender | July into August | Thompson, Rick & Thompson, Criss | --NR-- |
| 'Irish Moon' | Medium | Unknown | - | - | Moore, Jeff | --NR-- |
| 'Iron Curtain' | Medium | Hybrid | Near-White | June into July | Asch, Stuart | .2000 |
| 'Iron Sky' | Small | Sport | Pale-Lavender | August | Van Eechaute, Danny | .2012 |
| 'Iroquois' | Large | Hybrid | Near-White | July | Wade, Van | .2007 |
| 'Island Heartbreaker' | Large | Unknown | - | July into August | Blake, Amanda | .2016 |
| 'Island Waves' | Large | Hybrid | - | June | Blake, Amanda | .2016 |
| 'Itty Blue' | Small | TC Sport | Pale-Lavender | July into August | Zilis, Mark | .2011 |
| 'Ivatine Taylor' | - | Unknown | - | - | Unknown | --NR-- |
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