Propagation of ‘Carolina Sapphire’ Smooth Arizona Cypress by Stem Cuttings: Effects of Growth Stage, Type of Cutting, and IBA Treatment
Abstract Stem cuttings of ‘Carolina Sapphire’ smooth Arizona cypress [Cupressus arizonica var. glabra (Sudw.) Little ‘Carolina Sapphire’] consisting of 30 cm (12 in) terminals or distal [terminal 15 cm (6 in)] and proximal [basal 15 cm (6 in)] halves of 30 cm (12 in) terminals were taken on three dates associated with specific growth stages (semi-hardwood, hardwood, and softwood). Cuttings were treated with indolebutyric acid (IBA) in 50% isopropanol ranging from 0 to 16,000 ppm (1.6%) and placed under intermittent mist. Regardless of cutting type and auxin treatment, cuttings rooted at each growth stage. Overall percent rooting was highest during the hardwood stage (70%), followed by the semi-hardwood stage (44%). Softwood cuttings exhibited the lowest overall rooting (33%). At each growth stage, percent rooting, root count, and root dry weight varied depending on cutting type and IBA treatment. Rooting percentages ≥70% were attained at the semi-hardwood and hardwood growth stages for particular treatment combinations.