Effect of Transplanting and Paclobutrazol on Root Growth of ‘Green Column’ Black Maple and ‘Summit’ Green Ash

Abstract

‘Summit’ green ash (Fraxinus pennsylvanica ‘Summit’) and ‘Green Column’ black maples (Acer nigrum ‘Green Column’) were transplanted and treated with paclobutrazol (PBZ) to study its effect on root growth after transplanting. PBZ increased root extension growth of transplanted ‘Green Column’ maples in the first year after treatment, prior to the onset of above-ground growth regulation. Root growth of transplanted ‘Summit’ ash was not affected by PBZ. Transplanting reduced extension growth of regenerated roots in the first year for ‘Green Column’ maples with no effect on root dry weight. In ‘Summit’ green ash transplanting increased root extension growth in the second year, and root dry weight in both years.