The following is a list of rhododendron cultivars and species which have gained the Royal Horticultural Society's Award of Garden Merit. They are mostly hardy evergreen shrubs with abundant, brilliantly-coloured, trumpet-shaped flowers, often in large spherical trusses. The group known as azaleas are often (but not always) more compact with smaller flowers and leaves, and may be evergreen (subgenus Tsutsuji) or deciduous (subgenus Pentanthera). Most rhododendrons bloom for a short period in late spring (April to May in the temperate Northern Hemisphere). They are seen at their best in a woodland setting with light dappled shade, in humus-rich acid soil.[1]
Maximum dimensions are shown in metres.
| name | species | type | colour | Height | Spread |
|---|---|---|---|---|---|
| R. arborescens[2] | white/pink | 4.0 | 4.0 | ||
| R. bureavii[3] | pink/white | 2.5 | 2.5 | ||
| R. calophytum[4] | pink (pale) | 8.0 | 8.0 | ||
| R. davidsonianum[5] | pink (pale) | 4.0 | 2.5 | ||
| R. decorum[6] | white | 8.0 | 2.5 | ||
| R. falconeri[7] | white | 12.0 | 4.0 | ||
| R. fulvum[8] | pink | 4.0 | 4.0 | ||
| R. luteum[9] | deciduous azalea | yellow | 4.0 | 4.0 | |
| R. macabeanum[10] | yellow | 12.0 | 12.0 | ||
| R. makinoi[11] | pink | 2.5 | 2.5 | ||
| R. orbiculare[12] | pink (rose) | 2.5 | 2.5 | ||
| R. pachysanthum[13] | pink (pale) | 1.5 | 2.5 | ||
| R. pseudochrysanthum[14] | pink (pale) | 2.5 | 2.5 | ||
| R. racemosum[15] | white/pink | 2.5 | 2.5 | ||
| R. rex[16] | white (cream) | 12.0 | 8.0 | ||
| R. rex subsp. fictolacteum[17] | white (cream) | 12.0 | 8.0 | ||
| R. rex subsp. rex[18] | white or pink | 12.0 | 8.0 | ||
| R. sinogrande[19] | yellow | 12.0 | 8.0 | ||
| R. viscosum[20] | white/pink | 2.5 | 2.5 | ||
| R. williamsianum[21] | pink (rose) | 1.5 | 1.5 | ||
| 'Albert Schweitzer'[22] | pink (pale) | 4.0 | 2.5 | ||
| 'Alexander'[23] | evergreen azalea | orange | 0.5 | 0.5 | |
| 'Alice'[24] | rose pink | 2.5 | 2.5 | ||
| 'Bashful'[25] | pink (pale) | 1.5 | 1.5 | ||
| 'Berryrose'[26] | deciduous azalea | salmon pink | 2.5 | 1.5 | |
| 'Blaauw's Pink'[27] | evergreen azalea | salmon pink | 1.0 | 1.0 | |
| 'Blewbury'[28] | white | 1.5 | 1.5 | ||
| 'Blue Danube'[29] | evergreen azalea | blue (violet) | 2.5 | 1.5 | |
| 'Blue Peter'[30] | blue (violet) | 2.5 | 2.5 | ||
| 'Bouquet de Flore'[31] | deciduous azalea | pink/yellow | 2.5 | 1.5 | |
| 'Canzonetta'[32] | evergreen azalea | rose pink | 1.0 | 1.0 | |
| 'Cecile'[33] | deciduous azalea | salmon pink/yellow | 2.5 | 2.5 | |
| 'Chinese Silver'[34] | R. argyrophyllum subsp. nankingense | pink | 4.0 | 2.5 | |
| 'Cilpinense'[35] | pink (pale) | 1.1 | 1.1 | ||
| 'Cornell Pink'[36] | R. mucronulatum | deciduous | pink (pale) | 2.5 | 1.5 |
| 'Crane'[37] | white | 1.0 | 1.0 | ||
| 'Crest'[38] | yellow (pale) | 4.0 | 4.0 | ||
| 'Curlew'[39] | yellow (pale) | 0.5 | 0.5 | ||
| 'Cynthia'[40] | rose-pink | 8.0 | 8.0 | ||
| 'Daviesii'[41] | deciduous azalea | white/yellow | 1.5 | 1.5 | |
| 'Dopey'[42] | red (crimson) | 2.5 | 2.5 | ||
| 'Dora Amateis'[43] | white | 1.0 | 1.0 | ||
| 'Dreamland'[44] | pink (pale) | 1.5 | 1.0 | ||
| 'Egret'[45] | white | 0.5 | 1.0 | ||
| 'Elisabeth Hobbie'[46] | red (crimson) | 0.8 | 0.8 | ||
| 'Elsie Lee'[47] | purple | 1.0 | 1.0 | ||
| 'Fabia'[48] | orange/pink | 2.5 | 2.5 | ||
| 'Faggeter's Favourite'[49] | white/pink | 2.5 | 2.5 | ||
| 'Fantastica'[50] | red/white | 1.0 | 1.0 | ||
| 'Fastuosum Flore Pleno'[51] | blue | 4.0 | 4.0 | ||
| 'Fireball'[52] | deciduous azalea | red (scarlet) | 2.5 | 2.5 | |
| 'Furnivall's Daughter'[53] | pink/maroon | 4.0 | 4.0 | ||
| 'Gartendirektor Rieger'[54] | pink (pale) | 1.5 | 1.5 | ||
| 'Gibraltar'[55] | deciduous azalea | yellow/red | 1.5 | 1.5 | |
| 'Ginny Gee'[56] | pink (pale) | 0.5 | 1.0 | ||
| 'Golden Torch'[57] | yellow (pale) | 1.5 | 1.5 | ||
| 'Goldkrone'[58] | yellow | 1.5 | 1.5 | ||
| 'Gomer Waterer'[59] | pink/yellow | 2.5 | 2.5 | ||
| 'Gristede'[60] | blue | 1.0 | 1.0 | ||
| 'Hachmann's Marlis'[61] | pink (rose) | 1.5 | 1.5 | ||
| 'Hachmann's Polaris'[62] | pink (purple) | 1.5 | 1.5 | ||
| 'Hachmann's Porzellan'[63] | white/yellow/green | 1.5 | 1.5 | ||
| 'Hino-crimson'[64] | evergreen azalea | crimson | 0.5 | 0.5 | |
| 'Hinomayo'[65] | pink (pale) | 1.0 | 1.0 | ||
| 'Homebush'[66] | deciduous azalea | pink | 1.5 | 1.5 | |
| 'Hotspur Red'[67] | deciduous azalea | red (scarlet) | 1.5 | 1.5 | |
| 'Hydon Dawn'[68] | pink (pale) | 1.5 | 1.5 | ||
| 'Hydon Hunter'[69] | pink (rose) | 1.5 | 1.5 | ||
| 'Johanna'[70] | evergreen azalea | red (carmine) | 1.0 | 1.0 | |
| 'Kate Waterer'[71] | pink (rose) | 2.5 | 2.5 | ||
| 'Klondyke'[72] | deciduous azalea | orange/yellow | 2.5 | 2.5 | |
| 'Kluis Sensation'[73] | red (scarlet) | 2.5 | 2.5 | ||
| 'Koichiro Wada'[74] | R. yakushimanum | pink/white | 1.5 | 1.5 | |
| 'Lady Clementine Mitford'[75] | pink (peach) | 2.5 | 2.5 | ||
| 'Lavender Girl'[76] | pink (mauve) | 2.5 | 2.5 | ||
| 'Lem's Cameo'[77] | pink/red | 2.5 | 2.5 | ||
| 'Lem's Monarch'[78] | pink/white | 2.5 | 2.5 | ||
| 'Loderi King George'[79] | pink (pale) | 4.0 | 4.0 | ||
| 'Loderi Pink Diamond'[80] | pink (pale) | 4.0 | 4.0 | ||
| 'Loder's White'[81] | white | 2.5 | 2.5 | ||
| 'Lord Roberts'[82] | red (crimson) | 2.5 | 2.5 | ||
| 'Markeeta's Prize'[83] | red (scarlet) | 2.5 | 2.5 | ||
| 'Merganser'[84] | yellow (primrose) | 1.0 | 1.0 | ||
| 'Mid-winter'[85] | R. dauricum | purple | 1.5 | 1.5 | |
| 'Moerheim'[86] | blue (violet) | 1.0 | 1.0 | ||
| 'Mother's Day'[87] | evergreen azalea | red (crimson) | 0.7 | 0.7 | |
| 'Mrs A.T. de la Mare'[88] | white | 2.5 | 2.5 | ||
| 'Mrs Charles E. Pearson'[89] | pink (pale) | 4.0 | 2.5 | ||
| 'Mrs Furnivall'[90] | pink (rose) | 2.5 | 2.5 | ||
| 'Mrs T.H. Lowinsky'[91] | white/orange | 2.5 | 2.5 | ||
| 'Myrtilloides Group'[92] | R. campylogynum | lavender pink | 0.5 | 0.5 | |
| 'Nancy Evans'[93] | yellow | 1.5 | 1.5 | ||
| 'Nancy Waterer'[94] | yellow | 2.5 | 2.5 | ||
| 'Narcissiflorum'[95] | deciduous azalea | yellow | 2.5 | 2.5 | |
| 'Niagara'[96] | evergreen azalea | white | 0.6 | 0.6 | |
| 'Olga'[97] | yellow/pink | 1.5 | 1.5 | ||
| 'Openwood'[98] | R. yunnanense | semi-evergreen | pink (pale) | 8.0 | 4.0 |
| 'Palestrina'[99] | evergreen azalea | white | 1.5 | 1.0 | |
| 'Panda'[100] | yellow/pink | 1.5 | 1.5 | ||
| 'Patty Bee'[101] | yellow (pale) | 1.0 | 1.0 | ||
| 'Penheale Blue'[102] | yellow (pale) | 1.0 | 1.0 | ||
| 'Percy Wiseman'[103] | white (cream) | 2.5 | 2.5 | ||
| 'Persil'[104] | deciduous azalea | white/yellow | 2.5 | 1.5 | |
| 'Pink Cherub'[105] | pink | 1.5 | 1.5 | ||
| 'Pink Pancake'[106] | pink (salmon) | 0.5 | 1.5 | ||
| 'Praecox'[107] | pink (rose) | 1.5 | 1.5 | ||
| 'Princess Anne'[108] | yellow (pale) | 1.0 | 1.0 | ||
| 'Ptarmigan'[109] | white | 0.9 | 0.9 | ||
| 'Ramapo'[110] | purple (violet) | 1.0 | 1.0 | ||
| 'Razorbill'[111] | pink (rose) | 1.5 | 1.5 | ||
| 'Renoir'[112] | pink (rose) | 1.5 | 1.5 | ||
| 'Rock Rose'[113] | R. racemosum | pink | 1.5 | 1.5 | |
| 'Rosata'[114] | deciduous azalea | pink (rose) | 4.0 | 2.5 | |
| 'Saint Merryn'[115] | blue (violet) | 4.0 | 2.5 | ||
| 'Satan'[116] | red (scarlet) | 2.5 | 2.5 | ||
| 'Scarlet Wonder'[117] | red (scarlet) | 1.5 | 1.5 | ||
| 'Silver Slipper'[118] | white/yellow | 2.5 | 2.5 | ||
| 'Squirrel'[119] | evergreen azalea | orange | 1.0 | 1.0 | |
| 'Strawberry Ice'[120] | deciduous azalea | pink/orange | 2.5 | 2.5 | |
| 'The Honourable Jean Marie de Montague'[121] | red (crimson) | 2.5 | 2.5 | ||
| 'Tidbit'[122] | yellow (cream) | 1.0 | 1.5 | ||
| 'Tortoiseshell Wonder'[123] | salmon pink | 2.5 | 2.5 | ||
| 'Vintage Rosé'[124] | pink (rose) | 1.0 | 1.0 | ||
| 'Vulcan'[125] | red (scarlet) | 1.5 | 1.5 | ||
| 'Vuyk's Rosyred'[126] | pink (rose) | 1.0 | 1.5 | ||
| 'Vuyk's Scarlet'[127] | red (scarlet) | 1.0 | 1.5 | ||
| 'Wee Bee'[128] | pink/red | 0.5 | 1.0 | ||
| 'White Lights'[129] | white | 1.5 | 1.5 | ||
| 'Yaku Fairy'[130] | R. keiskei var. ozawae | yellow (lemon) | 0.5 | 1.0 |
