Finding the root flare is generally easy, just look for where the trunk becomes roots. Why is it important to identify this region before planting? Improper planting depth is a major cause of tree, shrub, and woody perennial failure. The root flare should always be at grade. The roots should be underground while the trunk or stem remains above ground.
While it’s easy to find the proper planting depth for bare-root stock, it’s much more difficult with container or B&B plants. Don’t be shy about removing the burlap or the top layer of container media. If you are making a purchase, it’s probably a good idea to ask first.
Some species such as wetland-adapted plants won’t mind if they are planted a little too deep, but many others won’t tolerate it. If the roots cannot get enough oxygen to survive, they will try to create a new system of adventitious roots. These types of roots cannot supply enough water to the plant, putting it in a state of chronic drought.
Excess moisture and lack of oxygen from being planted too deep sets the plant up for attacks by pests and diseases.
The best response is to dig the plant up and re-plant at the right depth.
The best preventative is to develop your flair for finding the root flare before planting.
Dickson Tree Management & Beautification Board 