Gardening: Help available for those with damaged trees

Nancy Szerlag
Special to The Detroit News

In last week’s column I wrote about “mulch mountains” – that is, layering mulch too deeply around trees and banking it up next to the tree’s trunk –  and how these practices can shorten the lives of trees.

The root flare at the base of the tree is vital to its surviving and thriving.

The good news for those who inherited trees surrounded by mulch mountains is that  a trained tree doctor, known as a certified arborist, has the tools and knowledge to possibly repair the damage and extend the life of your tree.  

If  the tree is small and planted fairly recently, you can do the job yourself.  Begin by using a shovel and hand cultivator to remove all the mulch piled up against the tree and on the surface of the soil, being sure to expose the root flare. That’s the area at the base of the tree trunk that widens as the primary roots begin to develop.

If the mulch has been in place for a period of time, you will see fine roots that have grown up into the mulch. Cut these away with well-sharpened hand pruners.  Be sure to cut away any roots that grow sideways and are on their way to encircling the tree.  Circling roots can slowly strangle a tree and shorten its life.  Next fill in any voids with top soil, but not so deep you bury that primary root flare. Then spread 2 to 3 inches of mulch around the tree, taking care to keep it away from the trunk.  

Here’s a website that includes a good video that shows how an arborist frees a tree from a mulch mountain that has been in place for several years or longer. One of the secrets to success is the compressed-air excavation tool, often referred to as a tree space, used to blow the soil from the secondary roots that have grown above the root flares without damaging the major roots.

In this video, "This Old House" landscape contractor Roger Cook and certified arborist Matt Foti save a tree from mulch suffocation:

Used to remove the soil and exposing the root flares, these air spades in the hands of a professional can also help repair damage done to trees that have been planted too deeply by removing the soil and exposing the root flares. A properly planted tree's root flare will be exposed just above the level of the soil. If a tree looks like a lollipop stick stuck in the ground, it’s planted too deeply and this, too, can shorten the life of the tree.  

To find a certified arborist in your area, go to and enter your ZIP code.

Nancy Szerlag is a master gardener and a Metro Detroit freelance writer. Her column appears Fridays in Homestyle. To ask her a question go to and click on Ask Nancy. You can also read her previous columns at