Traditional organic mulch, such as wood chips or shredded bark, has long been the standard for landscaping beds, primarily because it suppresses weeds, retains soil moisture, and offers a clean aesthetic. While the decomposition process enriches the soil with organic matter, this natural breakdown requires annual replenishment, incurring recurring material and labor costs. Homeowners and landscapers often seek alternatives for a longer-lasting solution, a different visual appeal, or a product that avoids attracting pests like termites near structures. Exploring non-traditional materials allows for the development of low-maintenance, permanent landscapes.
Permanent Inorganic Alternatives
One major category of alternatives includes materials that do not decompose, offering a permanent groundcover solution that eliminates the need for annual reapplication. Stone and gravel are popular choices, ranging from fine pea gravel and crushed granite to larger river rock or marble chips. These materials offer a wide array of textures and colors, are highly effective at suppressing weed growth and preventing soil erosion, and their permanence translates to significant long-term savings.
The size and type of stone affect its performance; smaller, angular crushed stone tends to interlock and stay in place better than smooth, round river rock or pea gravel. Lighter stone surfaces reflect solar radiation, which helps keep the soil beneath them cooler in hot climates, though darker stones absorb and radiate heat. Pumice stone, a lightweight volcanic rock, is a unique option that insulates well while still allowing water and air to pass through to the soil.
Recycled materials offer another durable, non-decomposing option, with shredded rubber being the most common, typically sourced from recycled tires. Rubber mulch is known for its longevity, lasting up to 20 years, and its ability to provide a soft, cushioned surface, making it a popular choice for play areas. Unlike stone, rubber does not compact and is effective at retaining soil moisture, though it does not contribute any nutrients to the soil as it is inert. A drawback to rubber is its potential to absorb significant heat, which can raise the temperature of the surrounding air and soil. Inorganic materials like rubber and stone are less attractive to common pests such as carpenter ants and termites, which is an advantage when landscaping near a home’s foundation.
The Strategy of Living Groundcovers
A different approach involves using a dense planting of low-growing plants, often referred to as “living mulch.” This strategy replaces inert material with a cohesive layer of vegetation that performs the functions of weed suppression and moisture retention. Living groundcovers provide aesthetic benefits with dynamic textures and colors that change throughout the seasons, offering a softer, more natural look than stone or rubber.
The dense foliage creates a canopy that shades the soil, moderating temperature swings and significantly reducing water evaporation. Unlike inorganic materials, living groundcovers actively contribute to soil health by building organic matter and improving soil structure as their roots grow and decompose. They also foster a healthier microbial environment, which benefits nearby shrubs and trees.
Examples of effective living mulch include creeping thyme, which is drought-resistant and fragrant, and sedum, a tough, succulent plant that thrives in hot, dry, poor soil conditions. Other suitable options are ajuga (bugleweed) and mondo grass, which are excellent for filling in spaces between larger plants. While the initial planting requires more attention than spreading a material, once these plants form a dense mat, they become a low-maintenance, self-sustaining system requiring no annual replenishment.
Practical Considerations for Installation
Implementing any alternative groundcover requires thorough preparation to ensure long-term success. The first step involves the complete removal of existing weeds and debris, followed by proper grading to ensure a level surface and appropriate water drainage away from structures. This preparation is especially important for permanent materials, as correcting issues later requires removing the entire layer of stone or rubber.
For all loose inorganic materials, such as gravel, stone, and shredded rubber, installing a commercial-grade landscape fabric beneath the material is highly recommended. This barrier prevents the groundcover from sinking into the underlying soil over time and acts as an effective secondary barrier against weed penetration. Without a separating layer, the stone or rubber can slowly mix with the soil, leading to a muddy appearance and reduced effectiveness.
A frequently overlooked requirement for loose materials is the need for robust edging, such as metal, plastic, or stone borders. Strong edging is essential for containing the material and preventing it from migrating into adjacent lawn areas or pathways, especially on sloped sites or areas with heavy rain. When switching from organic mulch to an inorganic alternative, it is necessary to adjust watering practices, potentially requiring less frequent but deeper watering.