Influence of Cutting Maturity and Growth Regulator on Vegetative Growth and Flowering in Hydrangea macrophylla under Subtropical Pot Culture

Abstract

This study investigated the effects of cutting maturity, growth regulator concentration, and growing media on vegetative and floral traits of Hydrangea macrophylla L. under subtropical pot culture in Bhubaneswar, Odisha. Uniformly rooted softwood, semi-hardwood, and hardwood cuttings were transplanted into pots and grown under 75% shade net conditions. Treatments included different levels of Indole-3-butyric acid (IBA) and growing media (sand, perlite, vermiculite, soilrite). Softwood cuttings consistently exhibited superior performance in plant height (18.51 cm), leaf area (130.15 cm²), flower head diameter (14.08 cm), and earliest flower bud initiation (43.57 days). They also recorded maximum flower longevity (97.85 days). Hardwood cuttings produced more leaves at 45 and 60 days after planting, especially under control and IBA 250 PPM, but showed delayed flowering. Growth regulators had mixed effects, with control and IBA 250 PPM outperforming IBA 500 PPM in most traits. Perlite was the most effective medium for shoot elongation and leaf production. These results suggest that softwood cuttings combined with low IBA concentrations and well-drained media like perlite enhance ornamental performance in Hydrangea macrophylla under subtropical conditions.