Rooting Response of Stem Cuttings of Shantung Maple (Acer truncatum) to Time of Year, Cutting Position, and Auxin Concentration, Formulation, and Solvent

The influence of time of year, cutting position, and auxin concentration, formulation, and solvent on rooting of stem cuttings of shantung maple (Acer truncatum Bunge) was investigated in seven experiments. Softwood, semi-hardwood, second-flush softwood, and hardwood stem-tip cuttings were compared. Semi-hardwood cuttings [15 cm (6 in) in length] rooted best (55%). Auxin treatments [indole-3-butyric acid (IBA) or the potassium (K) salt of IBA (K-IBA)] ranged from 0 to 15,000 ppm (0 to 1.5%). Generally, rooting percentage decreased as auxin concentration increased. Cutting position (terminal or subterminal), auxin formulation (liquid or powder), and auxin solvent [water or ethanol:water (1:1 v/v)] did not affect percent rooting. Mean root number and mean root length were unaffected by all treatments. Results suggest shantung maple roots best from semi-hardwood cuttings treated with auxin at concentrations of 0 or 2,500 ppm (0.25%).