Grass doesn't always grow well underneath trees. The leafy canopy of the tree blocks the sun from reaching the grass, so it is unable to make food for itself through photosynthesis and it dies. The remaining patchy grass is aesthetically unpleasing. Even in cases where grass does grow properly under a tree, its removal may be necessary for a variety of reasons. There are a few different methods for safely removing the grass from the ground around trees.
Reasons to Remove Grass Around Trees
While a properly maintained lawn and tree can co-exist, there are several arguments favoring a grass-free zone around trees. Grass and trees have different water and fertilization needs, so keeping one well-fed may harm the other. Grass removes nutrients from the soil that the tree needs for growth. Some grasses, such as red fescue and bermudagrass, release chemicals that slow the growth of tree roots. Tools such as string-trimmers and mowers, used to keep the grass trimmed, can cut and injure tree trunks when they get too close to the tree.
Mulching around the tree in a radius about equal to the canopy is one way to kill the grass. A weed barrier fabric cut to fit around the tree, or layers of wet newspaper, four to eight sheets thick, laid out over the ground will block the sun from getting to the grass, but still allow water and air to get to the tree roots. According to Southern Nevada Water Authority, do not use materials made of plastic, as they do not allow oxygen and water to penetrate the soil and the tree can die. Instead, be sure to use weed barriers made of fabric or cloth. A 2-to 4-inch layer of mulch spread over the fabric or newspaper will weigh it down and make the area look nicer. After about a month, the grass will be dead. To prevent trunk rot, mulch should start several inches from the tree trunk, so the crown is left uncovered.
Digging up sod or patches of grass by hand can clear the area around the tree. The top layer of grass plus the thatch, which will reach 1 or 2 inches beneath the soil surface, all need removing to rid the area of grass. Mechanical tools such as tillers may cut the tree roots, which could damage or kill the tree. Shovels, hoes, trowels or dethatchers are all suitable for sod removal around tree roots. Any roots that are uncovered during the process can be buried with an inch of new topsoil to keep them healthy.
Herbicides such as glyphosate are available to kill the grass, but not harm the tree. The label will indicate if the herbicide is right for the grass you have and whether your particular tree is sensitive to it. Herbicides are best applied on a sunny wind-free day so the rain does not wash the chemicals away and wind does not blow the spray where it is not wanted. A cardboard cover will protect the tree so the spray does not get on the trunk or leaves. The manufacturer gives rates and instructions on the herbicide label so the herbicide can be applied in the way that is the most effective and least harmful.
- Bluestem Nursery: Eliminating Lawn Under a Tree or Around Valuable Plants You Wish to Keep
- The Columbian: Keep Grass Away From Tree Trunks
- Clemson Cooperative Extension: Maintaining Tree/Turfgrass Associations: A Plant Health Care Approach
- City of Santa Monica: Lawn Removal Guidelines
- Southern Nevada Water Authority: Tree Care During a Landscape Conversion
- University of California Cooperative Extension Riverside County: Questions and Answers to Citrus Management
- Fine Gardening: 4 Ways to Remove Sod
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