A native of Asia, the camphor tree (Cinnamomum camphora) is an evergreen known for its broad, shade-producing canopy and its ability to withstand urban pollution and stormy weather. It thrives in U.S. Department of Agriculture hardiness zones 9 to 11. Camphor trees can become problematic, however, due to their shallow roots, which frequently rise out of the ground and disrupt sidewalks and driveways. Root pruning can help remedy the problem, though it may lead to crown dieback and internal rot.
Remove soil from around the problem roots with a hand spade, digging carefully to avoid cutting or scratching the roots. Dig out enough dirt to reveal a clear, unobstructed view of the root that is to be cut.
Cut the problem root with a root- or branch-pruning saw. Apply a tree-rooting hormone compound if desired to encourage the wound to close quickly. Do not cut more than one-third of the tree's roots, and do not remove more than 25 percent of the roots from one side of the tree.
Place a root barrier in the soil to keep cut roots contained. According to the Texas A&M University Extension, root barriers should be embedded at a depth of at least 30 inches and made of an impermeable material. Root barriers should come above the surface of the ground to discourage roots from growing over them.
Backfill the area around the roots immediately with soil. Water afterward to close any air pockets that may have formed.
Things You Will Need
- Hand spade
- Root barrier
- Root- or branch-pruning saw
- Tree rooting hormone compound (optional)
- Ensure cutting tools are sharp, as a clean cut will form calluses more quickly than a rough, jagged one. Fertilizer may be added to the soil to aid tree growth, but not until the tree has had time to heal: about six to eight weeks after pruning during the growing season.
- Though cutting roots near the tree trunk may not lead to immediate problems, this harmful practice can cause the death of a tree a decade or more later. In some locations, such as Vancouver, British Columbia, the law mandates that root pruning must be done by a professional arborist.
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