Imagine wearing a belt around your waist that is being squeezed tighter and tighter, and you’ll get an idea of what girdling roots do to a tree.
The roots surface the soil and encircle the main trunk of the tree, causing the flow of water and nutrients to be restricted. The longer the tree deals with this, the weaker it becomes.
The most common cause of girdling roots is improper planting. When trees are in nursery containers for too long, the roots can circle the bottom of the pots, having nowhere else to go. When these roots are not loosened during the planting process, they can become girdling roots. Similarly, when a tree is planted in a hole that is too small, the same process occurs—the tree’s roots begin circling one another and in time develop into girdling roots.
Other causes include heavily compacted soil and close proximity to foundations or curbs.
The best way to prevent girdling roots, is to hire a professional. If you decided to do it yourself, dig the correct size planting hole. A common myth is “the deeper the better,” however, the planting hole should be two to three times as wide as the root ball and no deeper than the root ball. There should not be soil above the root flare or mulch up against the trunk. If there are roots encircling the base of the root ball, break these up before planting to allow for normal root development. Make sure to water a newly planted tree consistently.
If you suspect you have a tree with girdling roots you may need to consult with a certified arborist to avoid damaging the main trunk. In severe cases, girdling roots can compromise the tree’s stability and the tree may need to be removed. We recommend Ahlum & Arbor Tree Preservation should you need an expert.