| Cultivar Name | Plant Size | Leaf Color | Variegation | Var Color | Origin | Flower Color | Season | Source | Registered |
| 'Tasce' | Medium | Blue/Green | - | - | Unknown | - | - | Wade, Van | --NR-- |
| 'Tecumseh' | Giant | Blue/Green | - | - | Unknown | - | - | Wade, Van | --NR-- |
| 'Terra Marie' | Small | Med-Green | - | - | Hybrid | Pale-Lavender | July | Wade, Van | .2007 |
| 'Teton' | - | Dark-Green | - | - | Unknown | - | - | Wade, Van | --NR-- |
| 'Token' | Medium | Med-Green | - | - | Hybrid | Pale-Lavender | June into July | Wade, Van | --NR-- |
| 'Tokudama American Green' | Medium | Dark-Green | - | - | Hybrid | - | - | Wade, Van | --NR-- |
| 'Tomahawk' | Medium | Yellow | Marginal | Green | Sport | Pale-Lavender | July | Wade, Van | --NR-- |
| 'Tuffet' | Small | Med-Green | - | - | Unknown | - | - | Wade, Van | --NR-- |
| 'Tuscarora' | Large | Blue/Green | - | - | Unknown | Near-White | June | Wade, Van | --NR-- |
| 'Tweeter' | Miniature | - | Streaked | - | Unknown | - | - | Wade, Van | --NR-- |
| 'Tyendinaga' | Large | Blue/Green | - | - | Unknown | Near-White | June | Wade, Van | --NR-- |
| 'Tyendinata' | Giant | Dark-Green | - | - | Unknown | Near-White | July | Wade, Van | --NR-- |
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