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Girdling Roots - Metropolitan Forestry Services

Image of a backyard all sorts of different large trees.

What they are, why they occur, and what to do

General Description

Girdling roots are a serious problem for our landscape trees. We predict that girdling roots will be a major cause for tree decline in the next ten years. This is largely due to the number of landscapes planted in the last building and landscaping boom as well as to inappropriate planting practices. Girdling roots are roots that circle around the trunk of the tree, choking off the vascular system. This is somewhat similar to a pot bound house plant or container grown tree that has grown in the pot for too long. Girdling roots usually occur beneath the soil, so detection can be difficult. The problem is widely misdiagnosed, and many amateurs treat the symptoms rather than the real problem.

Symptoms of girdling roots are:

  • No natural root flare.
  • A flattened side of a tree, where it disrupts a more normal rounded shape.
  • Decay at the base of the trunk.
  • Crown decline- small new leaves, premature leaf coloration, leaf drop, and branch dieback.
  • Increased borer activity and other insect and disease problems.

Girdling roots are caused by:

  • Improper planting- too deeply or not preparing planting hole properly.
  • Volcano mulching- roots grow into mulch piled around the trunk instead of the surrounding soil.
  • Heavy clay or waterlogged soils.
  • Improper watering- where sprinkler systems not designed, installed, or adjusted properly are often the culprit.

Trees with a higher probability of girdling roots:

Norway Maples, Sugar Maples, Red Maples, Sweetgums, Lindens, and White Pines. If girdling roots are diagnosed early some relief is possible. The trunk can be excavated; girdling roots located, and surgically removed; this is best done during the dormant season. Follow up is important, as other roots may grow to encircle the trunk.

For a pdf copy of this factsheet: Girdling Roots

"Thank you so much for all the information you provide – the watering information, the emails and the flier. I read it all and have learned so much."

– Cynthia K.

Our goal is to provide you with the best possible service. If you are not satisfied with any treatment or completed job, we will resolve the situation to your satisfaction. We want to do our utmost to ensure your trees and shrubs are always 'green and growing'.