Tree and yard owners are often faced with the problem of a tree's surface roots. Tree roots that grow on the surface are difficult to mow or walk over and can effect 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 tree roots is not advisable. Trees that experience root removal and damage can express top death on the side the roots were harmed. Removing roots can also introduce rot into the base of your tree.
Adding supplemental soil can also harm your tree. Additional soil can reduce the concentration of soil oxygen needed by roots to survive. Tree's can begin to show symptoms immediately or decline over time.
Symptoms of Tree Root Injury
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.
Injury will vary by tree species, age, health of the tree, depth and type of fill and drainage. Trees that are usually severely injured by additional fill include:
- sugar maple
- many oaks, pines and spruces
Birch and hemlock seem less affected by root fill damage. Elms, willow, London plane tree, pin oak and locust seem least affected. Older trees and those in a weakened state are more likely to be injured than younger, more vigorous trees.
So How Do You Deal With Surface Roots?
Be kind to your tree and make adjustments to the landscaping plan. Don't grow your garden or plant small ornamental plants near a tree's root life support system. Introducing extra vegetative competition and is not good for the tree's critical root zone health and most plants used as cover will lose vigor and will not thrive.
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 grass or ground cover in among surface roots is often difficult, if not impossible to do because of natural tree root toxins..