| Mulch material |
Comments |
| chipped, ground, or shredded bark |
Attractive, slowly improves soil as it gradually decomposes. Relatively expensive. Medium- to coarse-sized particles are long-lasting and resistant to wind movement; fine-textured products favor weed seed germination. Can be placed over plastics or landscape fabric as a decorative material, but these synthetic materials can be difficult to remove once they begin to deteriorate. |
| chipped, ground, or shredded wood |
Medium- to coarse-textured products are long-lasting and resistant to wind movement. Sometimes inexpensive or free. May not stay in place on slopes. |
| black plastic (solid polyethylene) |
Very effective, widely available, relatively inexpensive but has many drawbacks: Restricts air and water movement. Drip irrigation under the plastic usually must used since overhead irrigation cannot penetrate it. Breaks down in a few months and is unattractive unless a top mulch is applied. Tends to tear and break readily, allowing weeds to grow through holes. Not the best choice for long-term weed control. |
| clear plastic |
Not recommended for weed control because it encourages weed growth unless the soil is solarized and the clear plastic is left in place. |
| compost |
Excellent source of organic matter; readily available or can be made. Commercial products commonly are composed of composted greenwaste. Because of its smaller particle size, applying and maintaining a 2-inch layer can be effective. May harbor weed seeds, especially if not properly composted. May promote root crown disease if applied to contact trunks. When irrigated overhead, holds a significant amount of water that is not available to plants. Can break down quickly and readily become infested by weeds germinating from windblown seeds. |
| geotextiles, or landscape fabrics (spun or woven polypropylene and polyester) |
Very effective, relatively long-lasting if covered with bark or other suitable mulch. Allow air and water penetration. Expensive, may be unattractive without a top mulch. Brands differ in effectiveness and resistance to ultraviolet (UV) light. |
| grass clippings and leaves |
Readily available, generally must be reapplied often. May contain weed propagules, e.g., seeds or bermudagrass stems. Mats and reduces water penetration, especially if not dried before application. Better if composted before use. |
| gravel and crushed stone |
Avoid using as mulch because over time they tend to become mixed in soil and are time-consuming and difficult to remove. If used, apply landscape fabric underneath to prevent soil and mulch from mixing, which favors weed growth and contaminates soil with rocks. |
| greenwaste |
Uncomposted yard and tree trimmings. A variable mixture including bark, grass, ground wood, and leaves. Relatively inexpensive. May contain weed or pathogen propagules if not well composted. Can increase problems from small vertebrate pests (e.g., voles). |
| paper, or sheet mulch |
Easy application. Can be purchased, typically in rolls. May be useful to decrease weed pressure until newly planted groundcover fills in open spaces. Tends to break or tear after transplanting or if walked on. Hinders air and water movement, so rain and overhead irrigation tend to run off, which can favor weed growth at the paper's edge. May create a hydrophobic (water-repellant) barrier. |
