Young Trees – Roots Growing in Mulch

Q: To make the base of our young trees look pretty we decided to add fresh mulch, cutting a circle six feet in diameter and two inches deep around the mulch bed to make it look professional. To our surprise we found quite a few tree roots right under the mulch. Now we are worried that we damaged some important root lines. Can we cut them back or should we cover them again?

A: Your discovery just goes to show how much trees enjoy having mulch over their roots. Dr. Kim Coder describes “root wars” going on under a tree that has lawn grass growing beneath the limbs. By mulching, you gave the trees an advantage in gathering moisture and nutrients. Turfgrass growing under a tree is not good because grass roots out-compete tree roots for water and fertilizer. For that reason, I recommend that grass NEVER be planted in the area under the branches of a young tree. Your trees won’t be harmed by your raking. Simply replace the mulch and cover the roots. As the tree canopy expands, expand the mulch beds and consider adding shade tolerant perennials like hosta and ferns under the trees.