Abstract
Flowering characteristics and effects of timing the cutting and pinching of flowers in Hydrangea serrata (Thunb.) Ser. were investigated in order to establish a pot plant cultivation system. Sixteen varieties most of which were the lateral branch-flowering types were used. In most of the cuttings, flower bud differentiation started in late-October and differentiated sepals developed in late-November. Sepals of ‘Hakusen’ and ‘Maiko Ajisai’ differentiated in late-December. Cuttings of ‘Shichihenge’ and ‘Shichidanka’ were planted in early-, middle- and late-June and the shoots were pinched 5 and 6 weeks after planting. The number of flower clusters of ‘Shichihenge’ gradually decreased with delay in the planting date of cuttings. Pinching promoted the emergence of lateral branches but decreased the number of flower clusters. These results indicate that a sufficient number of flower clusters develop in the lateral branch-flowering type of H. serrata when cuttings are planted in early-June and cultivated without pinching.
