Plant Growth Regulator Impact on Calibrachoa Branching and Performance

Plant growth regulators (PGR) are often used to enhance branching and hence increase the number of flowering shoots of many ornamental crops. In this study, the effectiveness of three PGRs, Augeo, Configure, and Florel, at two rates as a foliar spray on branching and plant performance of two cultivars of Calibrachoa sp. (‘Balcanapt’ Can-Can Apricot™ and ‘Balcanoa’ Can-Can Mocha™) were investigated in greenhouse experiments in two Texas locations (El Paso and Overton). Rooted cuttings were transplanted to 4 inch square pots and PGRs were applied as a foliar spray eight days after transplanting in both locations. To compare the efficacy of PGRs, a group of untreated and un-pinched plants served as un-pinched controls, and another group of untreated but pinched plants served as pinched controls. Results from El Paso indicated that 33 days after PGR application, plants sprayed with Augeo at 400 and 800 ppm had the best visual quality ratings in both cultivars and had more or a similar number of shoots compared to unpinched and pinched controls. Regardless of application rate, Configure and Florel did not improve branching of either calibrachoa cultivar. In Overton, 33 days after treatments, plants treated with Augeo at 400 and 800 ppm and Florel at 500 and 1000 ppm had better visual quality ratings compared to un-pinched controls, but were similar to the pinched controls. Configure treated plants at both locations did not improve plant branching and overall quality and resulted in a “witches broom” appearance.  However, Augeo produced plants comparable to pinching at both locations.  At El Paso, only the low rate of Florel produced plants comparable to pinched plants, but at Overton, both rates of Florel produced plants comparable to pinched plants.