Investigating the Rooting of Stem Cuttings of Five Mediterranean Sage Species (Salvia ssp.), as a Means for Their Wider Exploitation in Sustainable Horticulture

Salvia fruticosa, S. officinalis, S. pomifera ssp. pomifera, S. ringens and S. tomentosa have multiple potential uses in both floriculture and the pharmaceutical industry, with an emphasis on sustainable horticulture and landscaping. Developing efficient protocols for vegetative propagation is an important step for the exploitation of the above species. Thus, research was conducted on the effect of cutting origin (either greenhouse or wild mother plants), season of cutting collection (in November, February, May and August, indicative of the four seasons) and various indole-3-butyric acid (IBA) treatments (either Rhizopon dusting powder 0.5 % w/w IBA or immersion for 1 min in 0-6000 mg L-1 IBA solution) on the rooting of shoot-tip cuttings of the abovementioned Salvias spp. After IBA treatment, cuttings were placed for rooting in a 1:1 (v/v) peat-perlite substrate, under mist, for 2 weeks and on the greenhouse bench in semi-shade for another 4 weeks. Conclusively, more efficient rooting was succeeded by cuttings: i) of S. tomentosa, followed by S. fruticosa and S. pomifera ssp. pomifera, while S. officinalis was the most difficult to root, ii) from greenhouse plants, iii) collected in autumn or spring, and iv) treated with Rhizopon dusting powder, along with some concentrations of IBA solution, depending on the species and season, with the concentration of 1500 mg L-1 being satisfactorily effective in most cases. Higher dry weight values of the rooted cuttings were found in autumn.