| Rating | Plant | Thumbnail |
| Rhododendron 'Saffron Queen'
Rhododendron |  |
 | Rhododendron 'Saint Tudy'
Rhododendron
Hybridized by Magor and Harrison, 1961 |  |
| Rhododendron 'Sappho'
Rhododendron |  |
| | Rhododendron 'Sapporo'
Rhododendron
Additional info: (aka Hachmann's Sapporo) |  |
| Rhododendron 'Satan'
Rhododendron
Hybridized by Knap Hill |  |
| Azalea 'Scarlet'
Rhododendron
Additional info: (KeepsakeŽ Azalea Series) |  |
| Vireya cultivar 'Scarlet Beauty'
Rhododendron |  |
| | Dwarf Rhododendron 'Scarlet Wonder'
Rhododendron
Hybridized by Hobbie, 1970 |  |
| | Dexter Rhododendron 'Scintillation'
Rhododendron |  |
| Rhododendron 'Seaview Sunset'
Rhododendron | |
| Rhododendron 'Second Honeymoon'
Rhododendron |  |
| Azalea 'Sekidera'
Rhododendron |  |
| Dwarf Rhododendron 'Senator Henry M. Jackson'
Rhododendron | |
| | Rhododendron 'Seraphine'
Rhododendron
Hybridized by Heinje, D.. Jeddeloh, Germany, 1964 |  |
| Rhododendron 'Seta'
Rhododendron |  |
| Azalea 'Shakuna'
Rhododendron |  |
| | Rhododendron 'Shamrock'
Rhododendron
Hybridized by Ticknor, 1978 |  |
| Azalea 'Shirazz'
Rhododendron |  |
| Royal Azalea 'Sid's Royal Pink'
Rhododendron schlippenbachii | |
| Rhododendron 'Silver Edge'
Rhododendron |  |
| Rhododendron 'Silver Skies'
Rhododendron | |
| | Azalea 'Silver Slipper'
Rhododendron
Hybridized by Anthony Waterer, Knap Hill Nursery, Woking, UK
Additional info: (Knap Hill Hybrid) |  |
| Elepidote Rhododendron 'Silver Sovereign'
Rhododendron |  |
| Evergreen Azalea 'Silver Sword'
Rhododendron |  |
| | Azalea 'Sir Robert'
Rhododendron
Hybridized by Robin Hill |  |
| Rhododendron 'Slam Dunk'
Rhododendron | |
| Rhododendron 'Smoke Signal'
Rhododendron | |
| Yakushimanum Hybrid Rhododedendron 'Sneezy'
Rhododendron
Hybridized by Waterer
Additional info: (Seven Dwarfs series) |  |
| Snow Azalea 'Snow'
Rhododendron |  |
| Dwarf Rhododendron, Small-leaved Rhododendron 'Snow Lady'
Rhododendron
Hybridized by Lancaster, 1958 | |
| Rhododendron 'Snow Queen'
Rhododendron |  |
| | Azalea 'Snowbird'
Rhododendron
Hybridized by Biltmore Gardens, Asheville, North Carolina |  |
| | Azalea 'Soir de Paris'
Rhododendron |  |
| | Rhododendron 'Solidarity'
Rhododendron
Hybridized by Hank Schannen |  |
| Rhododendron 'Spatter Paint'
Rhododendron irroratum
Hybridized by C. Smith
Additional info: (aka Polkadot, Polka Dot) |  |
| | Azalea 'Speck's Brilliant'
Rhododendron
Hybridized by Belgium
Additional info: (Mollis hybrid) |  |
| Azalea 'Spek's Brilliant'
Rhododendron
Additional info: (Old Mollis-type hybrid) |  |
| Rhododendron 'Spellbinder'
Rhododendron
Hybridized by Leach, 1975 |  |
| Azalea 'Spicy Lights'
Rhododendron
Hybridized by University of Minnesota, 1987
Additional info: (Northern Lights Series) |  |
| Vireya Rhododendron St. Cecelia 'St. Cecelia'
Rhododendron |  |
