This study was conducted to investigate the effects of rooting promoters on rooting and seedling quality in Buddleja davidii ‘Empire Blue’, Hydrangea paniculata ‘Magical Candle’, Hydrangea arborescence ‘Annabelle’, Stephanandra incisa semi-hardwood cuttings. IAA and IBA (500, 1000, or 1500 mg･L-1 soaking for 30 minutes and 3,000 mg･L-1 dipping for 10 seconds) or RootoneTM were used as rooting promoter. In B. davidii ‘Empire Blue’, IBA 1,500 mg･L-1 soaking reduced rooting percentage than control, but the effect of rooting promoters was generally insignificant. Number of leaves and shoot length were reduced in RootoneTM and IBA 1,500, 3,000 mg･L-1 treatments. IAA 1,000~3,000 mg･L-1 and IBA 500 mg･L-1 treatments showed better mat formation than control. The rooting ratio of H. paniculata ‘Magical Candle’ increased to 66.7% in IBA 1,500 mg･L-1 soaking treatment compared with 26.4% in the control. The mat formation was higher in RootoneTM, IAA and IBA treatments compared to control, and root length showed longer tendency in IAA and IBA except RootoneTM. The rooting ratio of H. arborescence ‘Annabelle’ was highest at 70.8% in the control and auxin treatments showed negative effect on the rooting percentage except IAA 1,000 mg･L-1 soaking treatment. The mat formation was very poor in IBA 1,000 and 1,500 mg･L-1 soaking at 1.1 and 1.3, respectively. S. incisa showed high rooting percentage at RootoneTM (80%) and IAA 1,500 mg･L-1 (80%) treatments compared to control (51.7%). Root length and dry weight were high in IAA 1,500 mg･L-1 soaking treatment. As a result, B. davidii ‘Empire Blue’ and H. arborescence ‘Annabelle’ did not need rooting promoter for stem cuttings, and IBA 1,500 mg･L-1, IAA 1,500 mg･L-1 soaking treaments could be used to improve rooting and seedling quality of H. paniculata ‘Magical Candle’ and S. incisa semi-hardwood cuttings, respectively.

Introduction
 Methods
  Plant materials and experimental environment
  The effects of rooting promoters
  Growth measurement and statistical analysis
 Results and discussion
 Conclusions
 References

• Hyun Hwan Jung(National Institute of Horticultural & Herbal Science, RDA)
• Ki Young Park(National Institute of Horticultural & Herbal Science, RDA)
• O Hyeon Kwon(National Institute of Horticultural & Herbal Science, RDA)
• Bong Sik Yoo(National Institute of Horticultural & Herbal Science, RDA) Corresponding author