Sanguisorba 'Strawberry Fost' is a medium sized burnet with long-blooming white and frosted-pink, pipe cleaner-like flowers.

Sanguisorba 'All Time High' is a 6-8 foot tall burnet with fluffy, white, pipe cleaner-like blooms.

Sanguisorba 'Blackthorn' is a 2-3 foot tall burnet with long-blooming rosy-pink, bottlebrush flowers.

Saponaria x lempergii 'Max Frei' is a hybrid soapwort popular as a front of border perennial for English cottage-style gardens.

Scabiosa Flutter 'Deep Blue' has larger, deeper blue flowers than 'Butterfly Blue'. Popular with butterflies.

Scabiosa Flutter 'Pure White' produces glistening, pure white pompoms from spring through summer.

Scabiosa Flutter 'Rose Pink' has large pink pincushions all summer long perfect for humans and butterflies.

Scabiosa 'Giga Silver' is a pincushion flower with extra large, silvery white blooms.

Scabiosa columbaria 'Vivid Violet' offers large, glowing violet-pink pincushion flowers popular with butterflies.

Schizophragma hydrangeoides 'Moonlight' has 9" (23cm) clusters of flowers are ringed by flat lacy white bracts.

Schizophragma hydrangeoides 'Rosea' has 9"(23cm) clusters of flowers are ringed by flat lacy pink bracts.

Scrophularia macrantha has curious, bird-like, bright red, tubular flowers that bloom from early summer to frost.

Scrophularia macrantha Cardinale Red has curious, bird-like, bright red, tubular flowers that bloom from early summer to frost.

Scutellaria ovata or heartleaf skullcap has purple infused new growth followed by tubular purple flowers.

Scutellaria 'Pat Hayward' Sky's Edge is long-lived sage relative with long-blooming, violet-blue flowers from summer to fall.

Scutellaria resinosa 'Smoky Hills' is a dainty little sage relative with textured mounds of grey-green leaves and purple-blue early summer flowers.

Scutellaria suffrutescens or cherry skullcap is covered in bright pink to cherry red, snapdragon-like flowers from spring until fall.

Sedeveria 'Letizia' forms colonies of upright, trunked, bright green rosettes that can develop bright red tints with stress.

Sedeveria 'Markus' has forms apple green rosettes of attractive, pointed leaves.

xSedoro ‘Blue Elf’ is the first inter-generic hybrid between Sedum and Orostachys. It has steel-blue tufted rosettes topped with tight clusters of dark-pink flowers that attract bees.

Sedum ellacombianum 'Cutting Edge' is a mounding sedum with scalloped, spatula-shaped leaves with gold margins.

Sedum floriferum ‘Winter Mahogany’ is a creeping stonecrop with yellow flowers and green foliage that changes to burgundy red for autumn and winter.

Sedum nussbaumerianum 'Coppertone' has trailing stems in shades of amber and glowing orange.

Sedum ochroleucum 'Red Wiggle' is an outstanding stonecrop forming multi-colour carpets of cherry red, orange-red, and green.

Sedum pachyphyllum 'Rose' forms cute, short-trunked colonies with cylindrical, powder blue leaves like elongated jelly beans.