Putting Down Roots: Proper Planting Depth

Two people planting a tree.

How deep is too deep? Planting a tree incorrectly can have an immediate or long-lasting impact on the health of the tree. One of the most common mistakes is planting a tree too deep which can lead to an early death for the tree.

An easy way to determine the proper depth, no matter what size or species of tree you are planting, is to ensure that its “trunk flare” is above the surface of the soil. Trunk flare (also called “root flare”) is the section of trunk where it gets wider at the base of the tree and the trunk becomes roots.

Five steps for Planting a Potted Tree

  1. Removing excess soil. If you don’t see the trunk flare when removing the tree from its pot, gently brush off the soil that is covering it.
  2. Dig a hole that is only as deep as the root ball. The bottom of the trunk flare level should be level with the ground and the hole should be two to three times wider than the root ball to encourage the roots to spread.
  3. Fill the hole with the soil that you dug out and gently pack it down. Do not add any amendments or fertilizers to the hole as this can cause problems with watering and root development.
  4. Ensure the bottom of the trunk flare is level with the ground. The trunk flare is not always obvious on very young trees so if you’re not sure, plant the tree so that the top of the root ball is level with the surrounding ground.
  5. Apply a six to eight centimetre (two to three inch) layer of mulch around the tree. Keep mulch in a doughnut shape, making sure that the mulch is six to eight centimetres (two to three inches) away from trunk so that the flare is not buried. 

Follow up with proper care, including watering immediately after planting. For more information on how to properly plant your new tree, check out our How to Plant a Potted Tree or Shrub fact sheet or watch this short video showing you how a properly (and improperly) planted tree looks.

Homeowners in CVC’s SNAP neighbourhoods and Community Tree Project neighbourhood can request a free tree that CVC’s home planting team will deliver and help plant this fall. Let us show you how to plant a tree at the correct depth in your own yard!

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