By Ruth de Jauregui Updated April 20, 2021
Trees, shrubs, and other landscape and garden plants rely on roots to nourish their stems, branches, leaves, flowers, and seeds or fruits. Whether you’ve cut down a tree or you’re cleaning up the garden bed, root removal may be necessary before you can replant. Trees, shrubs and deep-rooted weeds can resprout or send up suckers from the roots left in the ground, so removing the larger roots can help mitigate resprouting without resorting to chemical controls.
Cleaning up the garden after you’ve harvested summer- and fall-ripening vegetables and fruits helps prevent the spread of diseases. Double digging the garden bed and raking out roots, sticks, rocks and other debris is one way to remove lots of small roots in the soil. Master Gardener Sandy Vanno recommends covering the garden bed with cardboard and wetting it down. Next, apply 2-inch deep layers of dead leaves, shredded paper, straw and wood ash with grass clippings, kitchen scraps, manure, coffee grounds and other green materials into a 3-foot-tall lasagna-style, no-dig compost pile to decompose over the winter. This prevents regrowth from any remaining roots while enriching the soil.
When preparing a garden bed, opportunistic weeds and grasses may sprout in the freshly turned and amended soil. Dandelions (Taraxacum spp.), hardy in U.S. Department of Agriculture plant hardiness zones 3 through 10, are particularly deep-rooted and tenacious, as any part of the root left in the ground will regrow. Soften the soil by watering; then use a root-digging tool to help you pull the entire root out with relative ease.
Tree Root Removal
Tree roots spread in a wide circle around a tree, often as much as twice the height of the canopy. A weeping willow (Salix babylonica), which grows up to 50 feet tall in USDA zones 2 through 9, may have roots that spread aggressively to 150 feet or more away from the trunk, according to the University of Florida IFAS Extension.
When removing a tree from the landscape, a tree service usually chips the trunk to a depth of 8 to 12 inches with a stump grinder. The main roots, however, remain in the soil. Iowa State University Extension reports that most tree roots grow in the top 18 inches of soil, and more than 50 percent are in the top 6 inches of soil. You can soften the soil by watering and then dig up the large shallow roots with a shovel. Deeper roots will naturally decay underground and don’t require removal unless you’re installing plumbing, a foundation or other hardscape.
Mechanical and Chemical Controls
Many trees and shrubs produce root sprouts after the plant is damaged or cut down. This survival mechanism may result in many small sprouts growing up through the lawn or landscape. Vigilance is essential if you wish to avoid chemical controls.
Whether dandelions or tree root sprouts, pull them up or cut them off as soon as they appear. Mow over root sprouts of trees or shoots of running bamboos (subfamily Bambusoideae), hardy in USDA zones 5 and up, to prevent regrowth. In two to three years, the Clemson Cooperative Extension reports that the remaining bamboo rhizomes or tree roots should be depleted of energy and stop resprouting.
Some tree species are persistent and may require additional controls to prevent regrowth. If the stump was left in the landscape, you can apply an herbicide immediately after cutting down the tree. Paint the outer edge of the cut surface with 2,4-D or a glyphosate product so that the tree can pull the herbicide down into the roots. If the stump is too old, SDSU Professor John Ball suggests drilling 1-inch-wide holes into it and filling them with a slow-release fertilizer. Cover with topsoil or mulch and allow the trunk and its attached roots to decompose naturally. [external_footer]