Edging around a tree creates a clean, intentional boundary between the lawn and the area immediately surrounding the trunk. This practice significantly improves the aesthetic appeal of the landscape by defining the transition zone. A properly edged border protects the tree trunk and delicate surface roots from mechanical damage caused by lawnmowers and string trimmers. This physical separation also reduces competition between turf grass and the tree for water and soil nutrients.
Preparing the Area and Essential Tools
The first step involves determining the appropriate size of the edged area. The ideal diameter extends to the tree’s drip line, the imaginary circle on the ground directly beneath the outermost tips of the branches. This zone is where the tree’s fine, water-absorbing feeder roots are concentrated, and maximizing this area benefits tree health. If the drip line is too large, aim for a minimum radius of two to three feet from the trunk to offer adequate protection for young trees.
Clearing the existing turf must be done with caution to avoid injuring the tree’s root system. Shallow, fibrous roots are often found just beneath the soil surface, especially near the trunk. The goal is to remove the grass without significantly disturbing the underlying soil or scraping the bark of exposed roots. If a section of turf proves difficult to lift, it may be covering a root, and that area should be cleared by hand instead of forcing a tool through.
Gathering the correct tools streamlines the process of cutting a uniform edge. A sharp, flat-bladed spade or a specialized half-moon edger is necessary for manual trenching. A garden hose or landscape marking paint is useful for laying out the desired circular or organic shape before digging begins. For initial clearing, a string trimmer can be used carefully, keeping the line parallel to the ground to avoid damaging the lower trunk.
Techniques for Cutting the Edge Line
Once the desired diameter has been established, the outline must be clearly marked on the ground using the garden hose or spray paint. This visual guide ensures the finished edge will be a smooth, continuous curve that complements the shape of the tree and the surrounding landscape. A neat, consistent boundary is achieved by following this line precisely.
Manual trenching is the method for creating a durable, natural-looking edge. Begin by plunging the spade or half-moon edger straight down along the marked line to create a vertical cut. This initial slice establishes the outside wall of the future border and serves as the clean separation from the turf grass. The depth of this cut should reach three to four inches to provide a barrier against shallow-running grass rhizomes.
After the initial vertical cut is complete, create an angled inner cut toward the tree. Angle the spade inward from the vertical line, removing the soil and turf between the two cuts to form a V-shaped trench. This angled profile forces grass runners to grow vertically to cross the trench, exposing them to desiccation or easy removal. The removed soil and grass clumps can be composted or repurposed elsewhere.
While manual trenching offers precision, a powered mechanical edger can achieve the same result faster, especially for larger areas. Mechanical edgers use a spinning blade to slice the turf along the guide line, instantly creating a defined, vertical wall. Whether using manual or mechanical tools, the resulting trench should be neat and consistent in depth and angle.
Filling and Maintaining the Border
With the physical edge established, the newly cleared area is ready for filling, which addresses the tree’s long-term health. Applying organic mulch, such as shredded bark or wood chips, helps conserve soil moisture and moderates soil temperature fluctuations. Mulch also breaks down over time, slowly releasing organic matter into the soil, benefiting the tree’s root environment.
Maintain a mulch layer two to four inches deep over the cleared area. This depth is effective for weed suppression and moisture retention without suffocating the roots, which require adequate oxygen exchange. Applying too thin a layer will not provide the intended benefits, while excessive depth can inhibit water penetration and gas exchange.
Avoid “volcano mulching,” which involves piling mulch high against the tree trunk. Mounding mulch against the trunk traps excessive moisture against the bark, leading to decay and the development of root collar rot. To prevent this, pull the mulch back three to ten inches from the trunk, ensuring the root flare—the base where the trunk widens—remains exposed. The resulting mulch bed should resemble a flat donut shape, not a cone.
Maintaining the clean border requires minor attention once the initial cut is made. The trench should be redefined annually in the early spring using the spade or edger to prevent the surrounding lawn from encroaching. For a more permanent solution, materials like metal, plastic, or stone edging can be installed within the cut line to provide a lasting barrier. Regular inspection of the mulch bed for depth and position ensures the tree remains healthy and the border stays clean.