| Cultivar Name | Plant Size | Origin | Flower Color | Season | Source | Registered |
| 'Ukulele Lady' | Medium | Unknown | - | - | Weirether, Jon | --NR-- |
| 'Ultramarine' | Large | Hybrid | Pale-Lavender | August | Zilis, Mark | .2003 |
| 'Uncle John' | Medium | Hybrid | Near-White | July | Nyikos, Frank | .2000 |
| 'Uncle Shorty' | Giant | Unknown | Near-White | June into July | Schulz, Ed | .2017 |
| 'Unique' | Giant | Hybrid | Light-Purple | - | Fisher, Eunice V. & Ruh, Peter | .1991 |
| 'Uniquely Go Big or Go Home' | Giant | Unknown | - | July into August | Rosenberg, Marlene & Goodrich, Jon & Miller, Jeff | .2014 |
| 'Unruly Troll' | Large | Unknown | Pale-Lavender | June into July | Schulz, Ed | .2014 |
| 'Upper Echelon' | Medium | Hybrid | - | June into July | Ward, Dr Dick & Ward, Jane | .2013 |
| 'Ute' | Large | Unknown | - | - | Wade, Van | --NR-- |
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