Removing grass from the area immediately surrounding a tree’s trunk is highly recommended for promoting long-term health and vigor. This practice involves clearing the turf in the critical zone around the base of the tree. Growing turf right up to the trunk is a common landscaping practice that unintentionally harms the tree, particularly young or stressed specimens. Replacing this grass with a better alternative improves the growing environment.
How Grass Affects Tree Health
The presence of turfgrass directly beneath a tree’s canopy creates two main threats: resource competition and mechanical injury. Turfgrass has a dense, shallow root system that aggressively occupies the top few inches of soil, the same zone where a tree’s fine feeder roots are concentrated. This leads to competition for finite resources, specifically water and nutrients like nitrogen, which the grass often wins during dry periods. Studies show that when grass is removed, tree root development in the surface soil layers significantly increases.
The second major threat comes from routine lawn maintenance equipment. String trimmers and lawnmowers frequently nick or scrape the bark around the tree’s base, near the root flare. Even minor wounds compromise the protective barrier of the bark, providing entry points for pathogens and wood-decaying fungi. When the injury circles the trunk, it is called girdling, which disrupts the flow of water and nutrients, often leading to the tree’s decline and eventual death. Removing the grass buffer eliminates the need to operate damaging equipment near the trunk.
Safe Methods for Turf Removal
To create a healthy, clear ring around the trunk, first define the area you plan to clear. For young trees, aim for a minimum diameter of 3 to 5 feet, or as wide as the canopy allows, and widen this area as the tree grows. The safest method for immediate removal involves carefully scraping or shallow-digging the turf, taking care not to penetrate the soil deeper than two inches to avoid damaging the tree’s shallow roots. If you encounter resistance, it is a sign of a surface root, and you should move your digging slightly to avoid severing it.
A less labor-intensive, chemical-free alternative is to smother the grass. This is done by first cutting the grass low, then laying down four to ten overlapping sheets of newspaper or a layer of cardboard over the entire area. Wetting the material helps keep it in place and initiates decomposition, blocking sunlight and slowly killing the underlying grass. You must avoid using non-selective herbicides near the tree trunk, as the chemicals can be absorbed by the tree’s root system and cause significant damage.
Best Practices for Applying Mulch
Once the turf is removed, applying an organic ground cover like mulch is the next step to maximize tree health. Mulch helps by moderating soil temperature, reducing moisture evaporation, and suppressing weed growth that would otherwise compete with the tree’s roots. Organic materials like shredded bark or wood chips are recommended because they decompose over time, adding beneficial organic matter and nutrients to the soil.
The ideal depth for this layer is consistently between two and four inches, which is sufficient for weed suppression and moisture retention without suffocating the roots. The most important rule in mulching is to avoid the common mistake known as the “mulch volcano,” where the material is piled high against the trunk. Piling mulch against the bark traps moisture, which can cause the bark to rot and create favorable conditions for pests, disease, and the development of girdling roots.
Instead of a volcano, create a “mulch donut” by pulling the material back several inches, leaving a clear, dry space next to the tree’s trunk and the root flare. This practice ensures the bark remains dry, prevents the tree from growing adventitious roots into the mulch, and allows water and oxygen to penetrate the soil surface. A properly applied mulch ring protects the tree from mechanical damage and creates a stable, healthy environment for the fine feeder roots.