Every time I see the exposed roots of a tree in a lawn or park, I think of a little boy trying to enjoy his ice cream cone but ending up with skinned knees and sandy ice cream. It happened in Charleston’s Battery Park, not once but three times in an afternoon. Needless to say, I’ve been leery of tripping over exposed tree roots ever since. Let’s talk about what to do if you have exposed tree roots in your landscape.
Tree Roots Seldom Grow Deep
We tend to think of deep roots when we see a large healthy tree. In fact, most of the roots grow outward instead of straight down. There is a tap root, but the tree sends out most roots closer to the top of the ground (12 to 18 inches deep) in the layers of organic soil where they absorb critical nutrients, including oxygen and water.
The roots continue to grow, and eventually, as the root becomes thicker, it may push out of the ground. Fortunately, there are plenty more roots in the soil keeping the tree upright, so the exposed roots are not a huge concern. The problem compounds if there is extensive soil compaction from vehicles or construction, or soil erosion from rain or wind, leaving more roots exposed. The roots can become tripping hazards, damage lawn mower blades, and cause uneven sidewalks, driveways, or cracks in the foundation of a structure.
Should You Add Soil Over Exposed Tree Roots?
When the roots appear, the knee-jerk reaction may be to cut them off or pile soil around the tree to bury the roots. Neither is a good idea. Cutting the roots lessens the stability of the tree, reduces water uptake, and invites pests. Piling on a thick layer of soil cuts off essential oxygen to the tree roots, can cause the roots to grow and circle abnormally, and, when piled against the trunk, causes rot and invites pests and disease.
How To Manage Exposed Roots In Your Landscape
When exposed tree roots become a problem, choose one of these methods for a healthier tree and fewer hazards.
Add Hardwood Mulch
A ring of shredded or chipped hardwood mulch will eliminate the need to mow under the tree, increase soil moisture retention, and reduce tripping hazards. The mulch ring should be large enough to cover the surface roots and about 2 to 3 inches deep. It’s best to extend the mulch to the drip line of the tree where the tips of the horizontal branches end. Never create a volcano of mulch around the tree trunk. Leave several inches clear around the trunk to prevent trapping too much moisture that invites pests and disease. All of the mulch should be spread flat and evenly.
Plant a Ground Cover
Because exposed roots create a mowing hazard, adding a no-mow, shade-loving ground cover can hide the roots and add interest to your landscape. There’s no need to add additional soil; simply dig planting holes as small as possible, trying not to damage tree roots. Place the plants about one foot from the trunk and work your way outward, finishing by adding about two inches of organic mulch between the plants to help retain soil moisture…