Influence of soilless media on rooting and growth characteristics of ¿difficult to root¿ Damask rose (Rosa damascena Mill.) cuttings

Traditionally, plants of Rosa damascena Mill. (Damask rose) are propagated by cutting, grafting, layering or budding. Propagation of this species by cutting is associated with various problems such as prolonged production time and a low rate of adventitious root formation. Due to the high cost of peat as a growing medium, it is necessary to find an alternative. Rice husk, waste tea leaves and leaf compost, as organic compounds, are available in large amounts in northern Iran. The objective of this study was to evaluate the rooting response of Damask rose cuttings in various soilless media considering rooting and growth rate. This experiment was carried out in a completely randomized design with 3 replications and 12 treatment levels in a greenhouse at the Department of Horticultural Sciences, Tarbiat Modares University, Tehran, Iran. Data revealed that among growing substrates, sand combined with rice husk had the best effect on most of the parameters like, days to sprouting, rooting and sprouting percentage, number and length of roots, shoot number and shoot height as well as fresh and dry weight of root. Leaf compost positively affected the growth of cuttings, while waste tea leaves had unfavorable effects on rooting and growth parameters. In brief, rice husk and leaf compost could be used in rooting bed of damask rose cuttings, considering sustainability and economic aspects.