| Rating | Plant | Thumbnail |
| Rhododendron 'Babylon' Rhododendron | |
| Rhododendron 'Baden Baden' Rhododendron |  |
 | Rhododendron 'Balalaika' Rhododendron Hybridized by Hachmann, 1987 |  |
| Rhododendron 'Balsaminiflora' Rhododendron indicum |  |
 | Rhododendron 'Bambi' Rhododendron Hybridized by Wiseman, 1951; registered 1986 |  |
| Rhododendron 'Bambino' Rhododendron |  |
| Rhododendron 'Barmstedt' Rhododendron | |
| Rhododendron 'Bear Claw' Rhododendron | |
 | Vireya Hybrid 'Belisar' Rhododendron | |
| Catawba Rosebay, Catawba Rhododendron, Mountain Rosebay 'Belle Heller' Rhododendron catawbiense |  |
| Dexter Rhododendron 'Bellringer' Rhododendron | |
| Azalea 'Belva's Joy' Rhododendron | |
| Azalea 'Ben Morrison' Rhododendron |  |
| Rhododendron 'Ben Moseley' Rhododendron | |
| Azalea, Rhododendron 'Bengal' Rhododendron |  |
| Maddenia Rhododendron 'Bernice' Rhododendron | |
| Azalea 'Berryrose' Rhododendron Additional info: (Knap Hill hybrid) |  |
 | Rhododendron 'Besse Howells' Rhododendron Hybridized by Shammarello, 1964 |  |
| Azalea 'Betty Anne Voss' Rhododendron Hybridized by Robert Gartrell Additional info: ('Robin Hill' Series) | |
| Pink Swamp Azalea, Swamp Honeysuckle, Clammy Azalea 'Betty Cummins' Rhododendron viscosum | |
| Robin Hill Azalea 'Betty Layman' Rhododendron Hybridized by Robert Derby Gartrell Additional info: ('Oakland' x 'Heiwa') | |
| Azalea 'Bibiani' Rhododendron | |
| Azalea 'Big Deal' Rhododendron Hybridized by Mezitt | |
| Rhododendron 'Bikini Island' Rhododendron | |
| Rhododendron 'Biloxi Blues' Rhododendron Additional info: (aka Biloxi) | |
 | Rhododendron 'Bixby' Rhododendron Hybridized by Mezitt |  |
 | Kurume Azalea 'Blaauw's Pink' Rhododendron Hybridized by Kurume |  |
| Azalea 'Black Sport' Rhododendron | |
| Azalea 'Blaney's Blue' Rhododendron | |
| Azalea 'Blewbury' Rhododendron | |
| Azalea 'Bloom-A-Thon Pink Double' Rhododendron Additional info: (PPAF) | |
| Azalea 'Bloom-A-Thon Red' Rhododendron Additional info: (PPAF) | |
| Azalea 'Bloom-A-Thon White' Rhododendron Additional info: (PPAF) | |
 | Small-leaf Rhododendron 'Blue Baron' Rhododendron Hybridized by Weston Nurseries, 1981 |  |
| Rhododendron 'Blue Boy' Rhododendron |  |
| Azalea 'Blue Danube' Rhododendron |  |
| Rhododendron 'Blue Jay' Rhododendron |  |
| Azalea 'Blue Lagoon' Rhododendron | |
| Rhododendron 'Blue Pacific' Rhododendron |  |
| Rhododendron 'Blue Peter' Rhododendron Hybridized by Waterer & Crisp, mid-1930s |  |