Journal of Applied Horticulture. 2001: 3(1): 13-16

Interactions among rooting substrate, phenological stage of cuttings and auxin concentration on the rooting of Cotinus obovatus

Denny, G C; Arnold, M A

Department of Horticultural Sciences, Texas A&M University, Mail Stop 2133, College Station, TX 77843-2133, USA.

A study was conducted to determine the effects of substrate, phenological stage of cutting, and auxin concentration on the rooting of the ornamental Texas smoke tree (C. obovatus). Cuttings from new lush growing tips (softwood), partially matured tissues (semi-mature wood) and mature woody fully lignified cuttings from the previous season's growth (mature wood) were treated with either 0, 5000, 10 000 or 15 000 mg potassium salt of indole-butyric acid (K-IBA)/litre and placed in either 50% peat:50% perlite or 100% perlite rooting substrates. Cuttings were placed under an intermittent mist system in a greenhouse for 8 weeks. Softwood cuttings rooted in both substrates, but the 50% peat:50% perlite substrate produced better quality rooted cuttings. Softwood cuttings peaked at 8000 to 10 000 mg K-IBA/litre. Semi-mature wood and previous season's growth cuttings rooted only in the 100% perlite substrate. In 100% perlite substrate, the optimum concentration for semi-mature wood cuttings was ~12 000 mg K-IBA/litre, while mature wood rooting was maximized at 15 000 mg K-IBA/litre or more.