Simon Bamboo Variegated 'Singing Sixteen' Daylily
'Single Red' Hybrid Peony 'Sioux Falls' Coral Bells: sanguinea
'Sirius' Daylily Sisi
'Siskin Clock' Carnation: Dianthus 'Siskiyou Blue' Idaho Fescue
'Sissinghurst White' Jerusalem Cowslip 'Six Hills Giant' Catmint
'Sizzler Burgundy' Scarlet Sage: splendens 'Sizzler Lavender' Scarlet Sage: splendens
'Sizzler Lilac Bicolor' Scarlet Sage: splendens 'Sizzler Mix' Scarlet Sage: splendens
'Sizzler Salmon' Scarlet Sage: splendens 'Skeleton Key' Foamflower: Tiarella
Skullcap Skullcap, Bushy Blue
Skullcap, Pink Skullcap, Pink Texas
Skullcap: suffrutescens Skunk Cabbage
Skunk Cabbage: foetidus Sky Flower: grandiflora
Sky Pilot 'Purple Rain' Sky Vine
'Skyline Neon Lights' Garden Petunia 'Skyracer' Tall Moor Grass
'Skyrocket' Alumroot: Heuchera 'Skyrocket' Rockcress
Sleepydick Slender Blue Flag
Slender Verbena (spp.) Slime Lily
Slipper Flower: crenatiflora Slipper Flower: falklandica
Slipper Orchid 'Agincourt' Slipperwort
Slipperwort: falklandica 'Sly-Jenna' Florist's Chrysanthemum
Small Crowfoot 'Brazen Hussy' 'Small Gesture' Daylily
Small Globe Thistle (spp.) Small Globe Thistle 'Taplow Blue'
Small Leaf Sage (spp.) Small Leaf Sage Dwarf
Small Leaf Sage Golden Small Leaf Sage 'Icterina'
Small Leaf Sage 'Purpurea' Small Leaf Sage 'Rachels Gold'
Small Leaf Sage 'Sage Of Bath' Small Leaf Sage 'Tricolor'
Small Leaf Sage 'Variegated Berggarten' Small Leaf Sage 'Woodcote'
Small Woodland Sunflower Smallage
Small-Flowered Century Plant Smartweed (spp.)
Smartweed 'Speciosa (Firetail)' Smartweed 'Taurus'
Smartweed: capitatum Smartweed: emodi
Smartweed: polymorphum Smartweed: virginianum (spp.)
Smartweed: virginianum 'Compton's Form' Smartweed: virginianum 'Lance Corporal'
Smartweed: virginianum Variegated Smilax
'Smokey Rose' Alumroot: Heuchera Snail Bean
Snail Vine Snake Aloe
Snake Palm (spp.) Snake Plant (spp.)
Snake Plant 'Laurentii' Snake Plant 'Moonshine'
Snake Plant: zeylanica Snakebeard
Snakeberry Snake's Head Iris
Snakeshead Fritillary (spp.) Snap weed 'Bright Eye'
Snap weed 'Seashells' Snapdragon, Brazilian
Snapdragon, Climbing (spp.) Snapdragon, Climbing 'Jewels'
Snapdragon, Creeping (spp.) Snapdragon, Creeping 'Jewels'
Snapdragon, Dwarf 'Summer Skies' Snapdragon, Spured 'Canon J. Went'
Snapdragon, Summer 'AngelMist™ Purple Stripe' Snapdragon, Summer 'Carita Deep Pink'
Snapdragon, Summer 'Carita Purple' Snapdragon, Summer 'Carita White'
Snapdragon, Summer 'Serena Purple' Snapdragon, Summer 'Serena White'
Snapdragon, Trailing (spp.) Snapdragon, Trailing 'Jewels'
Snapdragon, Twining (spp.) Snapdragon, Twining 'Jewels'