Auxin Application to Stem Cuttings of Selected Woody Landscape Plants by Incorporation Into a Stabilized Organic Rooting Substrate

Abstract

Stem cuttings of Buxus sinica var. insularis ‘Wintergreen’, Elaeagnus x ebbingei , Ficus benjamina , Gardenia augusta ‘Radicans’, Ilex glabra ‘Nigra’, Ilex vomitoria ‘Nana’, Juniperus conferta ‘Blue Pacific’, Ternstroemia gymnanthera , and Trachelospermum asiaticum were inserted into a stabilized organic rooting substrate (plugs comprised of peat and a polymer binder) that had been soaked in water, aqueous solutions of K-IBA (15 to 75 ppm), or K-IBA + K-NAA (15 ppm + 7.5 ppm to 60 ppm + 30 ppm). Rooting and initial shoot growth responses were compared with cuttings receiving a basal quick-dip in K-IBA (1000 ppm) or K-IBA + K-NAA (1000 ppm + 500 ppm). Rooting percentage, number of roots per rooted cutting, and total root length per rooted cutting for cuttings rooted in auxin-treated plugs were similar to or greater than cuttings receiving a basal quick-dip; lesser results were obtained in a few cases with K-IBA + K-NAA. Percent of rooted cuttings with new shoots and shoot length per rooted cutting for cuttings rooted in plugs treated with K-IBA were mostly similar to cuttings receiving a basal quick-dip in K-IBA, while cuttings rooted in plugs treated with K-IBA + K-NAA exhibited similar or lesser results compared to cuttings receiving a basal quick-dip in K-IBA + K-NAA.