Effects of Various Planting Depths and Root Disturbances On Four Commonly Grown Nursery Trees

Basic knowledge of plant physiology indicates that a healthy root system is very important to a plant’s health and survival.  Some would argue that the root system is the most important anatomical structure to the plant’s health and survival.  There has been much debates over the root systems in production and outplant settings.  Two of the debated practices include planting depth and differing methods of treating pot-bound roots. The purposes of this study include: 1) What effect will depth of planting have on the overall growth of the plant. 2) What effect will depth of planting have on the overall hardiness of the plant.  3) What effect will four treatments have on pot-bound roots in upshifting. In 2009, two species of oaks, Quercus acutissima and Quercus rubra were planted into three gallon pots.  There were two planting depths from which the plants originated, planted at soil surface and planted deep.  From these two, four treatments were imposed: seeds at soil surface/planted deep; seeds at soil surface/planted high; seeds deep/planted deep; and seed deep/planted high. Plants were taken from the pots and were planted in the field on April 21, 2010, at The Ohio State University’s Waterman Farm (Columbus, OH). Syringa reticulata and Tilia cordata, which were in one-gallon pots in with roots that were pot-bound, were up-shifted on June 18, 2008, into 7- or 15-gallon pots.  There were four treatments imposed on the two genera, which included; undisturbed, four cuts through the root ball at N,S,E,W, removal of one inch of the root ball around the pot, and washing off the media from the roots.  Through one season of growth and overwintering in the flat roof cravo, significant death occurred throughout both species of oak.  Depth treatment also played a major factor in that seeds deep that were upshifted and planted deep sustained significantly less mortality than the other three treatments pooled over species.  The root disturbance of Syringa reticulata and Tilia cordata, indicated that, at the P < 0.055 level, T. cordata with four cuts N,S,E,W had significantly greater caliper than that of T. cordata that had the one inch removed from sides and bottom.  This would indicate that the species by treatment of Tilia increases caliper when no roots are taken away, as apposed to taking off the roots.