Stem cuttings of five evergreen and vie deciduous taxa were rooted after treatment with 0, 0.1, 0.3 or 0.8% indolebutyric acid (IBA) in talc, or with 0, 0.25, 0.5, 1.0 or 2.0% IBA in 95% ethanol or in 45% propylene glycol. Despite large differences in the rooting response of taxa to carriers and (or) IBA concentrations, propylene glycol-IBA treatments produced rooting in most taxa comparable to those of ethanol-IBA. Root numbers of the 14 taxa increased linearly or curvilinearly with increasing concentrations of IBA dissolved in ethanol or propylene glycol, as did percent rooting of six of the nine evergreen and four of the five deciduous taxa. Talc formulations were generally less effective than IBA in solution at comparable concentrations.

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Author notes

Plant material for this research was donated by Sheridan Nurseries, Georgetown, Ontario; Mori Nurseries, Niagara-On-The-Lake, Ontario; Niagara-Holland Nurseries, Niagara-On-The-Lake, Ontario; Willowbrook Nurseries, Fenwick, Ontario; and the Niagara Parks Arboretum and School of Horticulture, Niagara Falls, Ontario. The Root-Zone® bottom heat equipment was provided by Vary Industries Ltd., Grimsby, Ontario. Technical assistance was provided by Bob Hamersma. Bert Ediger assisted in the preparation of the graphs.

2Research Scientist.

3Associate Professor, Departments of Animal and Poultry Science and Mathematics and Statistics, University of Guelph, Guelph, Ontario, Canada N1G 2W1.

4Propagator, Moon Nurseries, Box 482, Quarry Road, Yardley, PA 19607.