River birch – Concrete

Q: We are considering planting a river birch tree seven feet from a driveway. I have been warned that these trees have roots that can ruin concrete. We were told by an inspector that we have an underground stream running under the yard that would attract tree roots instead.

A: It’s a myth that “underground streams” run beneath Atlanta landscapes. Tree roots are constrained by oxygen in the soil, so they usually only grow within 12 inches of the soil surface. If the soil is so hard that the roots can’t find oxygen beneath the soil, roots will creep along the top and buckle paved surfaces. Your planting area is a bit small but I think you can plant a birch. To avoid surface roots, thoroughly spade the soil seven feet in all directions from the spot where the tree will be planted. Block roots from going under the driveway by installing 18″ wide continuous aluminum flashing edgewise 16 inches deep at the margin of the pavement.

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