In this issue of the Root Zone blog: planting depth
I know that we have discussed this in other newsletters and at times in person but due to the frequency with which I, as a consulting arborist, see trees being planted too deep, it bears repeating.
Just this season alone, I have been called out to look at hundreds of young trees which were stressed with many different pathogens, ranging from insect, disease and fungi. Keep in mind, pathogens are opportunistic and most often attack stressed plants. This is what makes the planting depth of your trees and shrubs so critical.
Trees and plants come from the grower, most times with anywhere from 3 to 8 inches of soil on the top of the root ball. This makes it very difficult for installers, such as landscape professionals, to ascertain the top of the root flare. The root flare is the natural widening at the bottom of the trunk where the truncated roots meet the ground. This should be grade and no soil or mulch should be piled up in this area.
When planting new trees, care should be taken to inspect for the root flare to help determine proper planting depth. A great way to do this is to cut the twine at the top of the burlap, pull it back and physically remove any dirt that is piled up against the flare. As stated above, I have found as much is 8 inches piled up the trunk. Imagine if the hole is dug and the tree is improperly planted. You then add 3 inches of mulch on top of the roots. You now have a tree that could be almost a foot too deep! This is an awful way for a tree to start its life. It can lead to trunk and root decay, blow downs and disease. The reason this is so difficult to change is because in a production environment, landscapers and landscape architects will not take the time to do this process as it adds extra time and planting with each tree and can add hours where many trees are to be planted. We must decide up front whether we want to invest the money in planting properly or deal with a multitude of issues and eventually replace trees on the back end.
We could go into much greater detail here in terms of problems that result from planting depth but will save that for another day. If you would like more details, please call the office or email us. If you would like a copy of our own planting specification to aid you in your projects or to use as a spec for your landscaper, feel free to request that by email at firstname.lastname@example.org