University of Maryland Extension

Planted Too Deeply

tree planted too deeply in the ground
A tree planted too deeply looks like a telephone pole coming out of the ground

Many trees and shrubs are set too deeply from the time of planting (planting holes should be wider than deeper), they can also settle too deeply into the ground over time or are overmulched. These situations can contribute to trees and shrubs having too much soil piled up around their trunk causing plant decline. In addition, Nurseryman sometimes add to the problem by piling up extra soil at the trunk line as they prepare woody plants to go to market.

A planting depth of only one-inch too deep can cause trouble. It is not uncommon to see trees planted as much as three or more inches too deep. Deep planting causes bark deterioration at the soil line, which will eventually kill the plant. It usually takes a few seasons for a newly planted tree or shrub to die from this and therefore folks do not associate the decline of a plant with how it was planted.  

Various symptoms point to excessively deep planting. Some new growth may even develop each spring, only to die-off during the stress of summer. Advanced symptoms of depth-related stress are cankers and deep cracking of the bark. A canker is an area of dead tissue on a woody stem. Some shallow cracking of bark is normal for many trees as the trunk grows. A tree may survive until fall but may not survive the winter because of an insufficient storage of food reserves caused by the damaged bark. Deeply planted trees tend not to be very vigorous and look like they are struggling to grow. 

Remedy: A properly planted and established tree flares at the base of the trunk at the soil line where it joins the root system. If this is not visible, then be suspicious of deep planting or another problem such as girdling roots. Root collar excavation which is the removal of excess soil and mulch around the root collar can sometimes be helpful. Carefully remove the excess mulch or soil from the circumference of the trunk to the point where the trunk flares out into root growth. Arborists sometimes perform root collar excavation by using an air spade, a special tool powered by an air compressor. 

If the tree or shrub was recently planted it can be lifted and replanted. To avoid excessive settling in future plantings, do not loosen the soil in the bottom of the planting hole. It is also recommended to plant trees and shrubs with the top of the root ball slightly above the existing soil line. This practice is particularly helpful when planting in heavy clay soils that tend to drain poorly

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