In 1992 we planted a Northwoods maple in our yard in Brooklyn Park. We made...

Asked July 14, 2015, 1:29 PM EDT

In 1992 we planted a Northwoods maple in our yard in Brooklyn Park. We made the mistake of putting a circle around it with layered landscape brick. We filled it in with dirt and mulch. As I am sure you know, roots started growing at the level of the dirt. They are small in diameter. The tree seems health in general, but want to do something different with the landscape because the roots have now pushed up the landscape bricks. Do you have a suggestion as to how we could landscape around the tree?

Hennepin County Minnesota mulch problem planting under a tree

1 Response

Thank you for the question. You are wise to try to correct this situation because as you have discovered, the mulch built up around the base of the tree resulted in the tree sending roots up through it in search of oxygen and moisture. The roots can grow up and around the trunk causing girdling which can eventually kill the tree. Before you do any landscaping, the tree and the root system need to be examined for health. If possible, dig the mulch away from the trunk about 12 inches, all the way around and down to the soil line. Then try to get more of the mulch off all over to reduce the amount of it as much as possible. If the tree is of value in your landscape, we would recommend you seek the services of a certified arborist to help you. It will be a big job and special equipment might be needed to excavate down to the proper depth, away from the trunk, without damaging the tree. If trunk girdling roots are found, the arborist can assess what remedial action might be helpful. Once this situation is remedied, you can plan for more landscaping. A good resource for learning about landscaping under trees is Trees and Shrubs: Maintenance eXtension from the University of Minnesota at http://www.extension.org/pages/8979/trees-and-shrubs:-maintenance#.VVFUJCwtH_Q.

Read here to learn how to hire a certified arborist: http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/how-to-hire-a-professional-arborist/

Thank you for contacting Extension.