What to do With Surface Tree Roots in Your Yard

Dealing With Surface Tree Roots

Beech forest, Barazar, Gorbeia,
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Tree and yard owners are often faced with the problem of a tree's exposed surface roots. Tree roots that grow on the surface are difficult to mow or walk over and can affect the growth and health of nearby grass and ground covers. The usual response to remedy the situation is either to cut the roots or add fill soil over the roots and then replanting grass or ground cover.

  • Cutting out surface tree roots is not advisable. Tree roots offer structural support, provide a nutrient flow that supports growth and vigor and when damaged, attract pests and pathogens. Trees that experience root removal or serious root damage can express top canopy death on the side the roots were harmed. Removing roots can also introduce rot into the root, the base, and trunk of your tree.
  • Adding supplemental soil to cover roots can also harm your tree. You can add an additional cover (like mulch) over roots to smooth out the surface of the landscape. Adding extra dirt, however, can reduce the concentration of soil oxygen needed by roots to survive. Trees can begin to show symptoms immediately or decline over time.

So How Do You Deal With Surface Roots?

Be kind to your tree and make adjustments to your landscaping plan. Don't grow your garden or introduce small ornamentals near a tree's surface root system and ultimately its life support system. Introducing extra vegetative competition may or may not work but plants that heavily compete for nutrients and light is never good within the tree's critical root zone. The tree may not suffer but the cover plant will lose vigor, probably struggle to thrive and will cost you the price of the plant plus the planting time. 

A better way to deal with surface roots is to cut a bed around the offending root system and cover with coarse mulch.

Do not add more than an inch of extra soil. Trying to establish even a shade tolerant grass or ground cover in among the surface roots can often be difficult. It might be impossible to do, because of natural tree root toxins produced by certain tree species.

Symptoms of Tree Root Damage and Fill Injury

In addition to the root injury itself, other visible symptoms of injury may include small, off-color leaves, premature fall color, suckering along the main trunk and dead twigs throughout the canopy of the tree or even death of large branches.

The types of tree injury will vary by tree species, tree age, the health of the tree, root depth, type of fill and drainage. Trees that are usually severely injured by additional fill include:

Note on Soil Fill:  Birch and hemlock seem less affected by root fill damage than other species. Elms, willow, London plane tree, pin oak, and locust seem to be the least affected. Older trees and those in a weakened state are more likely to be injured than younger, more vigorous trees.