| Cultivar Name | Plant Size | Leaf Color | Variegation | Var Color | Origin | Flower Color | Season | Source | Registered |
| 'Saint Fiacre' | Small | Blue/Green | - | - | Hybrid | Pale-Lavender | - | Bowden, Roger | --NR-- |
| 'Sarah Kennedy' | Medium | Med-Green | Marginal | White | Nat-Sport | Light-Purple | August to October | Ford, Richard & Mary | .2004 |
| 'Sea Wave' | - | - | - | - | Unknown | - | - | Smith, Eric | --NR-- |
| 'Seawave' | Large | Blue/Green | - | - | Nat-Sport | Pale-Lavender | July into August | Smith, Eric | --NR-- |
| 'Serena' | Medium | Blue/Green | - | - | Unknown | Pale-Lavender | July | Hunt, Roger | --NR-- |
| 'Sheila West' | Large | Med-Green | Medial | Yellow | TC Sport | Pale-Lavender | July into August | West, Colin | --NR-- |
| 'Sherborne Profusion' | Medium | Blue/Green | - | - | Unknown | Pale-Lavender | June into July | Smith, Eric & BHHS | .1988 |
| 'Sherborne Songbird' | Large | Blue/Green | - | - | Unknown | Pale-Lavender | July into August | Smith, Eric & BHHS | .1988 |
| 'Sherborne Swallow' | Medium | Blue/Green | - | - | Unknown | Pale-Lavender | July | Smith, Eric & BHHS | .1988 |
| 'Sherborne Swan' | Large | Blue/Green | - | - | Unknown | Near-White | July into August | Smith, Eric & BHHS | .1988 |
| 'Sherborne Swift' | Medium | Blue/Green | - | - | Unknown | Near-White | July | Smith, Eric & BHHS | .1988 |
| 'Sienna Susan' | Large | Light-Green | Marginal | White | Nat-Sport | Med-Lavender | June into July | Walker, O. & Potts, C. | .2019 |
| 'Silver Spray' | Medium | Blue/Green | Marginal | White | Unknown | Pale-Lavender | July into August | Osbourne, Vera | .1991 |
| 'Silver Wedding' | Medium | Blue/Green | - | - | Hybrid | Pale-Lavender | July | Jolliffe, Thomas | --NR-- |
| 'Silvery Slugproof' | Medium | Blue/Green | - | - | Hybrid | Pale-Lavender | July into August | Grenfell, Diana | .1996 |
| 'Smith GL 20' | - | - | - | | Duplicate | - | - | Duplicate Name | --NR- |
| 'Snow Bunting' | Large | Blue/Green | Marginal | Yellow | Nat-Sport | Near-White | June into July | Ford, Richard & Mary | .2015 |
| 'Snow Cream' | Medium | Med-Green | - | - | Hybrid | Pure-White | August | Lewis, Alan & Summers, Alex | --NR-- |
| 'Snowden' | Giant | Blue/Green | - | - | Hybrid | Near-White | June into July | Smith, Eric & BHHS | .1988 |
| 'Spinners' | Large | Med-Green | Marginal | White | Unknown | Pale-Lavender | July | BHHS | .1988 |
| 'St. George's Gold' | Medium | Yellow | - | - | Hybrid | - | - | Grenfell, Diana & Bond, Sandra | --NR-- |
| 'Sunflower' | - | - | - | - | Unknown | - | - | Unknown | --NR-- |
| 'Susan Montgomery’s Ghost' | Medium | Med-Green | Streaked | White | Unknown | - | - | Unknown | --NR-- |
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