Question:
What is the proper planting depth for a tree?Answer:
The proper planting depth should position the tree so that the trunk flare is level with or slightly higher than the surrounding grade. This is not necessarily the container's height.
To determine the proper hole depth, examine the root mass to locate the trunk flare. The trunk flare is the natural widening at the base of a tree trunk where it transitions into the root system. Sometimes the trunk flare is buried by soil during the spring potting operation, at times by an inch or more.
The height of the root mass after the trunk flare has been located and excess soil removed from the top of the root ball is the correct depth for the planting hole. Avoid digging the hole deeper than the height of the root mass because the tree may settle deeper into the hole than intended.
Planting too deeply can cause trees to die within months of installation or lead to chronic problems, most notably stem-girdling roots, that are likely to significantly shorten a tree's life.
Learn more in these articles: What can i do if my tree was planted too deeply? and Tree Planting Basics.
Right: This young tree is positioned at the correct depth. The trunk flare is visible at the soil surface.
Right: This mature tree was planted at the correct depth and the trunk flare is visible at the soil surface.