Sunken tree


Hi, I had a deck built around a flowering dogwood tree last year. The tree was previously at ground level but appears to have sunken a couple of inches. Is it possible to dig the tree out and raise it to the level of the deck or is there another course of action you can recommend? The tree was planted 3 years ago in amended sandy soil and has been growing well.


Thank you for contacting the Toronto Master Gardeners. Could it be that your flowering dogwood had soil added around its base during construction of your deck ? It looks like it has either been planted too deeply, or soil has been added around it. To stay healthy, the root flare must be exposed. You should be able to see the top of the flare. If a tree is planted too deeply, it will slowly die, for several reasons. The bark at the soil line will rot, becoming subject to disease and insects. Trees have roots that grow horizontally, and most of them are in the top 6”-24” of soil. If the tree is planted too deeply, there will be less water and oxygen available to the roots. And planting too deeply is a common cause of girdling roots ( to which flowering dogwood (Cornus florida) is susceptible). The roots of trees that are planted too deeply tend to grow upwards towards the surface of the soil and circle the trunk, cutting off the flow of nutrients and water from the roots up the branches, and the flow of food produced in the leaves down to the roots.

You could try brushing away the soil from the base of your tree, to see if the root flare can be left exposed. If not, you can dig it up and replant at the correct depth. Spring is the best time for tree planting, but you could also do this in the fall, when the air temperature is cool. If you are going to replant, make sure that the soil under the roots has been firmly tamped down before putting the tree into the hole, to minimize sinking and settling after planting. You should also ensure that the planting site will accommodate the tree at maturity, at its full size. For C. florida, full size is 15’ – 30’ tall and wide. (I can’t be sure from your photo which variety or cultivar you have).

Here are some links with additional information that might be helpful :

Planting a tree successfully requires the correct planting depth

Girdling roots

Tree Care: The Planting Hole

Cornus florida

Good luck with your flowering dogwood !

July 28, 2021