Surface Roots on Sunset Maple Tree

Q: We have a new Maple Tree about four inches in diameter planted 2 years ago. This Spring there are many surface roots, fine but numerous in the mulch around the tree.

It is a Sunset Maple. Is this bad? The surface roots extend to the drip line.

Thanks. Tom Galinski, Wheeling WV

A: There could be a couple reasons you are finding surface roots in the mulch. The tree may have been planted too deep and the roots began growing toward the surface to try to get to the proper depth, and/or the mulch layer may have been too thick.

Mulch should be maintained at only 2-3" deep. Too thick of a mulch layer and roots will begin to develop into it. Although this sounds good, it is not. Roots are very vulnerable when they grow into the mulch. They need good soil of proper density to grow into.

Since the roots are visible, look for ones that grow on a tangent to the trunk and cut them, especially if they are near the trunk, or even within a foot of the trunk. You want the roots to grow away from the tree, like the spokes on a wheel.

If they grow crosswise, they can develop into stem-girdling roots. It can take years, even decades, for girdling roots to kill a tree, and you may have the opportunity now to prevent this from happening.

Place a layer of soil only deep enough to cover the roots by about an inch, firm it down either by lightly tamping with your foot or sprinkling with water, then apply 2" of mulch. Future additions of mulch should be based on how much mulch is present at the time you check.

In other words, don't add 2-3" of mulch every year, just maintain a mulch layer 2-3" deep. It's OK for the roots to be out near the dripline, they need to be that far and further, so this is normal root growth.

When you water, be sure to water deeply and infrequently versus shallow and often. By watering too shallowly, you encourage the roots to grow near to the surface. Water deeply, down to 6-12", and you'll encourage root growth below the surface where it belongs. Apply 1-2" of water every 7-10 days, factoring in whatever rainfall Mother Nature provides.

Fertilize once a year in either spring or fall, concentrating from half the distance to the dripline and out beyond it to encourage rooting into the surrounding soil.

If the tree was planted too deep, it may not be easy to correct the problem. Look at the base of the trunk for the flares that then go into the ground to form the root system. If you do not see these flares, then the tree may have been planted too deep.

If so, it may be necessary to raise the tree to the proper depth. This would be a big task, but may be necessary to save the tree. It could also be that too much soil and/or mulch was placed on top of the rootball, but only an on-site visit would be able to determine what is happening.

I recommend you have a qualified arborist inspect the tree to see if it is planted too deeply, or just needs some mulch adjustment. If the tree needs to be raised it should be done this year, otherwise it could be a long slow death for the tree, and you could be out both the tree and the money you spent to plant it.

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