| Cultivar Name | Plant Size | Leaf Color | Variegation | Var Color | Origin | Flower Color | Season | Source | Registered |
| 'Taffeta' | Medium | Dark-Green | - | - | Hybrid | Light-Purple | July | O'Harra, Russ | .1991 |
| 'Tall Paul' | Large | Dark-Green | Medial | Yellow | Unknown | - | - | Livingston, Ron | --NR-- |
| 'Tea at Bettys' | Small | Med-Green | Marginal | Yellow | Sport | Light-Purple | July into August | Ford, Richard & Ford, Mary | .2009 |
| 'Teddy Bear' (Falstad) | Small | Blue/Green | Medial | Green | Unknown | - | - | Falstad, C.H. | --NR-- |
| 'Teddy Bear' (Hosta Library) | Large | Dark-Green | - | - | Unknown | - | - | Unknown | --NR-- |
| 'Ted's Friend' | Small | Med-Green | - | - | Hybrid | - | - | Tompkins, Chet | --NR-- |
| 'Telly's Treasure' | Medium | Dark-Green | Streaked | Yellow | Unknown | - | July into August | Singer, Mary & Elslager, Ed | .2002 |
| 'Tennessee Grady' | Small | Yellow | Streaked | Speckles | Unknown | - | August to September | Freeman, Franc | .2011 |
| 'Terra Marie' | Small | Med-Green | - | - | Hybrid | Pale-Lavender | July | Wade, Van | .2007 |
| 'Terry' | Medium | Dark-Green | Marginal | Creamy White | Sport | Pale-Lavender | July | Owens, Clarence | .2002 |
| 'Terry witha Y' | Medium | Blue/Green | | | Nat-Sport | Pale-Lavender | July into August | Herold, Glenn | --NR-- |
| 'Terry's Goldilocks' | Small | Yellow | Marginal | White | Unknown | - | - | Shane, Terry | --NR-- |
| 'Tess Hoop' | - | - | - | - | Unknown | - | - | Holland (unknown) | --NR-- |
| 'The Duchess Dorothy' | Small | Light-Green | Marginal | White | Unknown | Pale-Lavender | June into July | Goodwin, Randy | .2019 |
| 'The Mighty Quinn' | Large | Blue/Green | Marginal | White | Sport | - | June into July | Solberg, Robert | --NR-- |
| 'Thea' | Medium | Med-Green | Streaked | White | Sport | Pale-Lavender | July into August | Stratham, Netta & Bond, Sandra | .1985 |
| 'Thelonius' | Medium | Blue/Green | - | - | Hybrid | Near-White | July into August | Ward, Dr Dick & Ward, Jane | .2009 |
| 'Theo's Blue' | Medium | Blue/Green | - | - | Hybrid | Med-Lavender | - | Zonneveld, Ben & Leydens, Theo | --NR-- |
| 'Theo's Green' | - | Med-Green | - | - | Unknown | - | - | Leydens, Theo & Van Eechaute, Danny | --NR-- |
| 'Theo's Red' | Medium | Med-Green | - | - | Hybrid | Med-Lavender | - | Leydens, Theo | --NR-- |
| 'Thor' | Medium | Med-Green | - | - | Hybrid | Pale-Lavender | August | Ruh, Peter | .1994 |
| 'Tiffany Twirl' | Medium | Dark-Green | - | - | Unknown | - | - | Tiffany, Barbara | --NR-- |
| 'Tim and Claire' | Medium | Dark-Green | - | - | Unknown | - | - | Zilis, Mark | --NR-- |
| 'Timothy' | Small | Dark-Green | Marginal | Yellow | Sport | Pale-Lavender | June into July | Ruh, Peter | .1998 |
| 'Tiny Alice' | Small | Yellow | Marginal | White | Unknown | - | - | Unknown | --NR-- |
| 'Tom Boy' | Medium | Yellow | - | - | Unknown | - | June into July | Benedict, Dr Ralph (Herb) & Benedict, Dorothy & Kuenster, Rod | .2010 |
| 'Tom Cat' | Small | Med-Green | Marginal | White | Unknown | Light-Purple | July into August | Lydell, Ransom | --NR-- |
| 'Tom Terrific' | Large | Yellow | - | - | Hybrid | Pale-Lavender | July into August | Solberg, Robert | .2019 |
| 'Tom Thumb' | Miniature | Med-Green | - | - | Unknown | - | - | Fransen, Marco | --NR-- |
| 'Tom's Baby' | Large | Light-Green | Streaked | White | Hybrid | Pale-Lavender | July into August | Dishon, Jim & Schmid, Tom | .2003 |
| 'Tom's Dream' | Medium | Med-Green | Streaked | Yellow | TC Sport | Light-Purple | July into August | Zilis, Mark | .2003 |
| 'Tonto' | Medium | Med-Green | Marginal | White | Sport | Pale-Lavender | July into August | Malloy, Alex | .2002 |
| 'Tootie Mae' | Medium | Blue/Green | Marginal | Yellow | Sport | Near-White | June into July | Anderson, Jim | --NR-- |
| 'Toots' | Medium | Med-Green | - | - | Hybrid | Pale-Lavender | - | Sugita, Hajime & Ruh, Peter | .1998 |
| 'Topaz' (Johnson) | Medium | Blue/Green | - | - | Hybrid | Light-Purple | July into August | Johnson, Greg | .2004 |
| 'Topaz' (Summers) | Small | Med-Green | | - | Sport | Pale-Lavender | July | Summers, Alex | --NR-- |
| 'Tough Howard' | Large | Dark-Green | - | - | Unknown | Pale-Lavender | July into August | Freeman, Franc & Freeman, Sally | --NR-- |
| 'Trisha's Sunny Paradise' | Small | Yellow | - | - | Sport | Deep-Purple | July | McHugh, Ed | .2012 |
| 'Trixi' | Miniature | Med-Green | - | - | Unknown | Med-Lavender | June into July | Dupre, Dirk | .2006 |
| 'Trudy's Angel' | Large | Blue/Green | Streaked | Yellow | Unknown | - | - | Van Wyke, Trudy | --NR-- |
| 'Tucker Tommy Little' | Large | Med-Green | - | - | Hybrid | Near-White | July | Stephens, Ray | .1991 |
| 'Tuff Howard' | Medium | Dark-Green | - | - | Unknown | - | June into July | Freeman, Franc | .2010 |
| 'Twinkles' | - | - | - | - | Duplicate | - | - | Duplicate Name | --NR-- |
| 'Tyler's Treasure' | Large | Blue/Green | Marginal | Yellow | Sport | Near-White | June | Isaacs, Charles | .1999 |
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