Landscape trees are increasingly being produced using container nursery systems in comparison with traditional field production practices (U.S. Department of Agriculture, 2007). In contrast to traditional field production, container production requires a series of transplanting events in which trees are sequentially transferred to larger containers (potting-up/up-canning). This may cause problems because trees can potentially be planted too deep or too shallow at each up-canning. Variability in planting depth, defined as the location of the root collar relative to soil surface (grade), is of particular concern because optimum planting depth may vary among species and may be dependent on cultural practices and/or environmental conditions (Arnold et al., 2005, 2007; Ball, 1999; Browne and Tilt, 1992; Day et al., 2009; Drilias et al., 1982; Gilman and Grabosky, 2004; Wells et al., 2006). Little is known about the effects of relatively small, yet cumulatively significant changes in transplanting depth during container production and there may be an opportunity to improve plant performance during container production and when transplanted in the landscape by improving transplanting practices. We suggest that changes in transplanting depth during container production may be a result of numerous interrelated nursery practices, including 1) inappropriate size of plant material to container size ratio at up-canning; 2) shrinkage and loss of substrate; 3) excessive filling of the container and compaction of substrate; 4) hiding graft unions or pruning scars; and 5) general carelessness or lack or training.
If trees are planted too deep during the production phase, the detrimental effects of below-grade planting may be compounded during landscape installation (Fare, 2005). The few studies conducted on the effect of planting depth during container production show contrasting results depending on container size, planting depths, and species used during container production (Fare, 2005; Giblin et al., 2005; Gilman and Harchick, 2008). Our goal in this study was to determine if transplanting practices during container production through two up-canning events would affect subsequent landscape performance. Therefore, a series of experiments was conducted on Ulmus parvifolia Jacq (lacebark elm), a common landscape tree in urban environments, to determine the effects of different transplanting depths during container production and the subsequent effects on landscape establishment. Specifically, we tested whether 1) trees that were initially planted with root collars below grade or above grade in container production and then brought back to grade during successive up-canning or when placed in the landscape performed as well as trees that were consistently planted with root collars at grade; and 2) below-grade planting in containers would exacerbate any adverse effects of below-grade planting in the landscape.
Armstrong, W. & Drew, M.C. 2002 Root growth and metabolism under oxygen deficiency 729 762 Waisel Y. , Eshel A. & Kafkafi U. Plant roots: The hidden half Marcel Dekker, Inc New York, NY
Arnold, M.A. , McDonald, G.V. & Bryan, D.L. 2005 Planting depth and mulch thickness affect establishment of green ash (Fraxinus pennsylvanica) and bougainvillea goldentree (Koelreuteria bipinnata) J. Arbor. 31 163 170
Arnold, M.A. , McDonald, G.V. , Bryan, D.L. , Denny, G.C. , Todd Watson, W. & Lombardini, L. 2007 Below-grade planting adversely affects survival and growth of tree species from five different families Arboriculture and Urban Forestry 33 64 69
Bunt, A.C. 1988 Media and mixes for container-grown plants: A manual on the preparation and use of growing media for pot plants 2nd Ed Unwin Hyman Ltd London, UK
Day, S.D. & Harris, J.R. 2008 Growth, survival, and root system morphology of deeply planted Corylus colurna 7 years after transplanting and the effects of root collar excavation Urb. For. & Urb. Greening 7 119 128
Day, S.D. , Watson, G. , Wiseman, P.E. & Harris, J.R. 2009 Causes and consequences of deep structural roots in urban trees: From nursery production to landscape establishment Arbor. & Urb. For. 35 182 191
Fare, D.C. 2005 Should potting depth be a concern for container trees? 25 28 Watson G. & Hewitt A. Trees and planting: Getting the roots right conference proceedings Morton Arboretum Lisle, IL
Giblin, C. , Gillman, J. , Hanson, D. , Johnson, G.R. & Weicherding, P. 2005 The effects of soil depth on the long-term health and frequency of storm damage to trees in the upper Midwest 33 39 Watson G. & Hewitt A. Trees and planting: Getting the roots right conference proceedings Morton Arboretum Lisle, IL
- Search Google Scholar
- Export Citation
Giblin, C. Gillman, J. Hanson, D. Johnson, G.R. Weicherding, P. 2005 The effects of soil depth on the long-term health and frequency of storm damage to trees in the upper Midwest 33 39 Watson G. Hewitt A. Morton Arboretum Lisle, IL
Gilman, E.F. & Grabosky, J. 2004 Mulch and planting depth affect live oak (Quercus virginiana Mill.) establishment J. Arbor. 30 311 317
Harris, J.R. & Gilman, E.F. 1993 Production method affects growth and post-transplant establishment of ‘East Palatka’ holly J. Amer. Soc. Hort. Sci. 118 194 200
U.S. Department of Agriculture 2007 Nursery crops, 2006 summary Agricultural Statistics Board, NASS, USDA 21 May 2009 <http://usda.mannlib.cornell.edu/usda/current/NursProd/NursProd-09-26-2007.pdf>.
U.S. Department of Agriculture, Natural Resources Conservation Service, Texas Agricultural Experiment Station, Texas State Soil and Water Conservation Board 1991 General Soil Map: Brazos County, TX Washington, DC
Wells, C. , Townsend, K. , Caldwell, J. , Ham, D. , Smiley, E.T. & Sherwood, M. 2006 Effects of planting depth on landscape tree survival and girdling root formation Arbor. Urban For. 32 305 311