Influence of Paclobutrazol on the Growth and Flowering of Camellia × Williamsii

Abstract Plant height and lateral shoot growth of Camellia × Williamsii ‘Waterlily’ and ‘Debbie’ were controlled effectively by foliar sprays or media drenches of paclobutrazol. A single foliar application of 500 mg·liter –1 paclobutrazol reduced height of both cultivars by ≈30%, and plants were considered commercially acceptable. The response did not carry over into subsequent years. Some rates of paclobutrazol increased the total number of open flowers, but there was a varied effect on flower abscission. Paclobutrazol treatment could prove a useful technique for the commercial production of camellias for temporary use as indoor flowering pot plants before subsequent planting in the landscape. Chemical name used: β-[(4-chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1 H -1,2,4-triazole-1-ethanol (paclobutrazol, ICI-PP333).