Plants
- Sheep's-bit Jasione montana
- Shell GingerAlpinia zerumbet
- Shepherd's-purseCapsella bursa-pastoris
- Shooting StarAnthericum saundersiae
- Shooting Stars, American CowslipDodecatheon media f. album
- Showy PrimroseOenothera speciosa
- Shrimp PlantJusticia brandegeana
- Shrub Rose
- Shrubby CinquefoilPotentilla fruticosa
- Siberian dogwoodCornus alba 'Sibirica'
- Siberian IrisIris sibirica
- Siberian Iris 'Papillon'Iris sibirica 'Papillon'
- Siberian Iris 'Persimmon'Iris sibirica 'Persimmon'
- Siberian Iris. 'Marcus Perry'Iris sibirica 'Marcus Perry'
- Siberian WallflowerCheiranthus Allionii
- SidalceaSidalcea
- Sidalcea oregana 'Partygirl'Sidalcea oregana 'Partygirl'
- Silene shafta 'Splendens'Silene shafta 'Splendens'
- Silver arrows cactusMammillaria nejapebsis
- Silver BirchBetula pendula
- Silver Birch, European White Birch, Warty birch, Common BirchBetula verrucosa
- Silver BushConvolvulus cneorum
- Silver Fir, Hedgehog fir, 'Glauca' Noble FirAbies pinsapo 'Glauca'
- Silver Lace Vine
- Silver Mound ArtemisiaArtemisia schmidtiana ‘Nana’
- Silver SageSalvia, Agentea
- Silver ScabiousScabiosa argentea
- Silver Speedwell, Spiked speedwellVeronica spicata ssp. incana
- Silver spurflowerPlectranthus argentatus
- Silver torch cactusCleistocactus strausii
- Silver-spiked SedgeCarex buchananii
- Silverado Sage
- Silverweed Potentilla anserina
- sinapis albasinapis alba
- Sir Thomas Lipton Rugosa Rose