PPDL Picture of the Week

July 20, 2015

Planting Depth Affects the Long-term Survivability of Trees

Kyle Daniel, Department of Horticulture and Landscape Architecture, Purdue University


When trees are planted in the landscape special attention is placed on transplant shock and the short-term survival, while little thought is typically given to the long-term effects of tree planting practices.  The average life expectancy of a tree planted in an urban area is estimated to be less than ten years (USFS) up to 28 years (Roman and Scatena, 2011).  Proper tree selection, digging the hole 1.5 times the width of the root ball, and removing soil to find the root flare are a few of the steps to ensure long-term survival.  Many times trees are planted too deep, with no visible root flare.  When a tree is planted too deep, decay, structural malfunctions, apical dieback, and an increase in abiotic and biotic stress can occur.  If the trees you are maintaining do not exhibit a root flare, remove the soil and/or mulch until the root flare is located.  Also, keep mulch away from the trunk of the tree when re-mulching.


A Purdue bulletin on tree installation can be found here: https://www.extension.purdue.edu/extmedia/FNR/FNR-433-W.pdf

​Click image to enlarge

Figure 1.  The root flare of a tree growing in a natural area.

Figure 2. A tree planted extremely deep in a parking lot island that resulted in a blow-over.

Figure 3. A tree planted deep in a mulch volcano.