The 2012 ASHS Annual Conference

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 Verbena sp. (‘Balazvelu’ Aztec™ Blue Velvet and ‘Balazwilro’ Aztec™ Wild Rose) were investigated in greenhouse experiments in two Texas locations (El Paso and Overton). Overton is in the humid sub-tropics while El Paso has an arid environment.  Rooted cuttings were transplanted to 4 inch square pots during mid-May 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. At Overton, 23 days after treatment, the quality rating was higher than the untreated-not-pinched for all of the treatments except Augeo at 800 ppm and Configure at 300 ppm.  Both Florel rates at 500 and 1000 ppm were better than the control.  Thirty three days after treatment, the quality rating, flower number, and shoot number was best on plants treated with Augeo at 400 and 800 ppm.  At El Paso, the PGR treated plants had lower visual quality rating regardless of cultivar. The effect of PGR on shoot number varied with cultivar.  Phytotoxicity was observed with all treatments in El Paso, but only with the high rate of Configure in Overton.  The difference in response to PGRs between locations is likely due to the difference in climate zone.