Plants
- Sister Violet, Woolly Blue Violet 'Freckles'Viola sororia 'Freckles'
- sisyrinchium "lucerne"sisyrinchium "lucerne"
- Sisyrinchium 'Aunt May'Sisyrinchium striatum 'Aunt May'
- Sisyrinchium 'Biscutella'Sisyrinchium 'Biscutella'
- Sisyrinchium. 'E. K. Balls'Sisyrinchium 'E. K. Balls'
- Skimmia 'Kew Green'Skimmia x confusa 'Kew Green'
- Skimmia 'Veitchii'Skimmia japonica 'Veitchii'
- Skimmia japonicaSkimmia japonica
- Skimmia japonica 'Kew White'Skimmia japonica 'Kew White'
- Skimmia Japonica 'Magic marlot'Skimmia Japonica 'Magic marlot'
- Skimmia japonica 'Rubella'Skimmia japonica 'Rubella'
- SkullcapScutellaria incana
- Sky Blue AsterAster azureus
- Sky PencilIlex crenata Thunb
- Slender SpeedwellVeronica filiformis
- Slipper Flower, CalceolariaCalceolaria integrifolia
- Slipper orchidPhragmipedium besseae
- Slipper orchid 'Don Wimber'Phragmipedium 'Don Wimber'
- Slipper orchid or moccasin flowerCypripedium calceolus
- Small cranberryVaccinium oxycoccos
- Small FleabanePulicaria vulgaris (Wildflower)
- Small-leaved CotoneasterCotoneaster microphyllus
- Small-leaved LimeTilia cordata
- smallflower hairy willowherbEpilobium parviflorum
- Smoke BushCotinus coggygria 'Royal Purple'
- Smoke-tree Cotinus coggygria
- Smooth AsterAster laevis
- Smooth SumachRhus glabra
- smyrnium olusatrumsmyrnium olusatrum
- SnakerootCimicifuga racemosa (Actaea)
- Snakes head fritillaryFritillaria melagris
- SnapdragonAntirrhinum majus
- Snapdragon, 'Floral Shower'Antirrhinum 'Floral Shower'
- Sneezewort (Wildflower)Achillea ptarmica (Wildflower)
- Snow CrocusCrocus sieberi 'Violet Queen'