Abstract

A new root promoting chemical, P-ITB (phenyl indole-3-thiolobutyrate) was compared with IBA (1H-indole-3-butanoic acid) for activity on 19 woody taxa. P-ITB at 0.5% was as effective as 0.5% IBA for the plants tested. For difficult-to-root taxa like Amelanchier arborea, Photinia × fraseri and Zelkova serrata, P-ITB promoted excellent rooting. The chemical is as effective as IBA and was not injurious at the 2.0% level.