• Ranunculus aconitifolius ‘Pleniflorus’
• Ranunculus acris
• Ratibida columnifera var. pulcherrima
• Reineckea carnea
• Reseda luteola
• Rheum ‘Ace of Hearts’
• Rheum alexandrae
• Rheum palmatum
• Rheum palmatum tanguticum
• Rheum rhabarbarum
• Rheum rhabarbarum ‘Glaskins Perpetual’
• Rheum rhabarbarum ‘Poulton’s Pride’
• Rhodohypoxis ‘Donald Mann’
• Rhodohypoxis milloides
• Rhodoxis ‘Fairy Snow’
• Rhodoxis ‘Hebron Farm Cerise’
• Rhodoxis ‘Im201208’ (FAIRY KISSES)
• Rhodoxis ‘Mrs. Betsy’
• Rhodoxis ‘Ria’
• Rhodoxis ‘Ruby Giant’
• Rhodoxis ‘Titia’
• Rodgersia ‘Badenweiler’
• Rodgersia ‘Borodin’
• Rodgersia ‘Bronze Peacock’
• Rodgersia ‘Die Anmutige’
• Rodgersia ‘Irish Bronze’
• Rodgersia ‘Joop Ploeger’
• Rodgersia ‘La Blanche’
• Rodgersia ‘Spitzentaenzerin’
• Rodgersia aesculifolia
• Rodgersia aesculifolia ‘Werner Mueller’
• Rodgersia pinnata
• Rodgersia pinnata ‘Chocolate Wings’
• Rodgersia pinnata ‘Die Schöne’
• Rodgersia pinnata ‘Hanna’
• Rodgersia pinnata ‘Superba’
• Rodgersia podophylla
• Rodgersia podophylla ‘Braunlaub’
• Rodgersia podophylla ‘Rotlaub’
• Rodgersia purdomii
• Rodgersia sambucifolia ‘Rothaut’
• Rodgersia sambucifolia ‘Rotstiel’
• Romneya coulteri
• Rosmarinus officinalis
• Rosmarinus officinalis ‘Blue Rain’
• Rosmarinus officinalis ‘Blue Winter’
• Rosmarinus officinalis ‘Capri’
• Rosmarinus officinalis ‘Compact’
• Rosmarinus officinalis ‘Corsican Blue’
• Rosmarinus officinalis ‘Fota Blue’
• Rosmarinus officinalis ‘Miss Jessop’s Upright
• Rosmarinus officinalis ‘Prostratus’
• Rosmarinus officinalis ‘Tuscan Blue’
• Rudbeckia ‘Sun Ka-Ching’
• Rudbeckia fulgida ‘Forever Gold’
• Rudbeckia fulgida ‘Goldsturm’
• Rudbeckia fulgida ‘Little Goldstar’
• Rudbeckia fulgida ‘Pot of Gold’
• Rudbeckia fulgida var. deamii
• Rudbeckia hirta ‘Kissing SmileyZ’
• Rudbeckia hirta ‘Laughing SmileyZ’
• Rudbeckia laciniata ‘Goldquelle’
• Rudbeckia maxima
• Rudbeckia nitida ‘Herbstsonne’
• Rudbeckia nitida ‘Juligold’
• Rudbeckia occidentalis ‘Black Beauty’
• Rudbeckia occidentalis ‘Green Wizzard’
• Rudbeckia subtomentosa ‘Little Henry’
• Rudbeckia triloba ‘Prairie Glow’
• Ruellia humilis
• Ruta graveolens