Question of the Week Number 1: April 19, 2018
“We’re getting large numbers of surface roots beneath a couple of our trees. Should we be concerned? What can we do about them?”
Trees’ roots grow larger, just as their limbs do. As they do, they swell up and out of the soil.
90 percent of any tree’s roots are in the top foot of soil. It stands to reason, since rainfall and nutrition come into the soil from the top of the ground, so that’s where the trees’ roots need to be to compete with grasses and other short vegetation.
Many people think that soil has eroded from beneath their trees and they bring in fill soil. However, the roots grow up through that new soil as well, and before too many years they end up with a mound – and the people still have exposed roots.
Here are some options…
• Trim off any small roots that cross over one another so they don’t end up girdling one another.
• Remove any roots that threaten your foundation, patio, walks or driveway. Make your cuts as far away from the trunk as you can to leave as much of the root in place as possible. This is best done in fall, after the hot, dry weather of summer has passed.
• Don’t obsess over a few large, exposed roots. They’re as much a part of everyday life as the metal I-beams we see in stores and restaurants. No big deal.
• Since grass probably isn’t thriving in all the shade beneath the tree anyway, consider a shade-tolerant groundcover that can also function to conceal the roots. Liriope, regular mondograss, purple wintercreeper euonymus and, in areas with excellent drainage, English ivy are all good choices.