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%).

Propagation substrates can strongly influence rooting success of stem cuttings. Eastern redcedar (Juniperus virginiana L.) chips (ERC) have been suggested as a propagation substrate component. This study investigated ERC as a perlite substitute in a perlite:sphagnum peat moss (3:1 v/v) rooting substrate. Stem cuttings of coleus [Solenostemon scutellarioides (L.) Codd], English ivy (Hedera helix L.), forsythia (Forsythia ×intermedia Zab.), lantana (Lantana camara L.), and spreading euonymus (Euonymus kiautschovicus Loes.) were rooted in substrates containing increasing concentrations of ERC hammer-milled to pass a 4.8 mm (0.19 in) screen. All species rooted well (≥ 95%) in all substrates except forsythia which rooted poorly in all substrates (8 to 36%). ERC concentration did not affect mean root number or mean root length in any species except spreading euonymus where mean root number peaked at 0 and 100% ERC content and mean root length decreased with increasing ERC content. Bulk density, container capacity, and total porosity increased as ERC replaced perlite. Physical properties of all substrates were suitable for cutting propagation. ERC can effectively replace perlite in rooting substrates for many ornamental species.

Stump sprouts of stooled caddo sugar maple (Acer saccharum Marsh. subsp. saccharum) (caddo maple) and shantung maple (A. truncatum Bunge) were propagated by mound layering. In early summer, shoot bases were wounded and treated with 0, 10,000, 15,000, or 20,000 ppm (0, 1.0, 1.5, or 2.0%) indole-3-butyric acid (IBA) dissolved in 50% ethanol or 0, 5,000, or 10,000 ppm (0, 0.5, or 1.0%) of the potassium (K) salt of IBA (K-IBA) dissolved in water. Shoot bases were covered with a commercial growing substrate containing bark, Sphagnum peat moss, and perlite and retained by plastic rings 38 cm (15 in) in height. Rooted shoots were harvested in fall or late winter. Auxin concentration influenced rooting of caddo maple and shantung maple mound-layered shoots. Rooting peaked at 15,000 ppm (1.5%) IBA for both caddo maple (71%) and shantung maple (34%). Mean root number for caddo maple, but not shantung maple, increased as IBA concentration increased. Differences in mean root length were not significant. Results suggest caddo maple can be successfully propagated by mound layering. For shantung maple propagation, mound layering was less successful, so alternatives such as stem cuttings should be considered.