| Situation | Use Fabric? |
|---|---|
| Under gravel paths or driveways | Yes — prevents gravel sinking into soil |
| Under bark mulch in planted borders | No — causes more problems long-term |
| Around established trees and shrubs | No — restricts root growth and soil health |
| Under raised bed paths | Yes — suppresses weeds in non-planted areas |
| In vegetable gardens | No — use cardboard or thick mulch instead |
What Is Landscape Fabric?
Landscape fabric (also called weed membrane or geotextile) is a woven or non-woven synthetic sheet designed to block weed growth while allowing water and air through. You lay it on the soil surface, cut holes for plants, and cover it with mulch for appearance.
The idea is simple and appealing: a permanent barrier that eliminates weeding forever. In practice, it works well in specific situations but causes significant problems when used in planted garden borders — which is unfortunately where most gardeners put it.
The Problems with Landscape Fabric
Most professional gardeners and horticulturists now advise against landscape fabric in planted borders. Here’s why:
Weeds still grow on top. Within a year or two, decomposing mulch and wind-blown soil create a thin layer of organic matter on top of the fabric. Weed seeds germinate in this layer, and their roots grow into the fabric weave, making them much harder to pull than weeds growing in bare soil.
Soil health declines. Fabric blocks earthworms from reaching the surface, prevents organic matter from being incorporated into the soil, and disrupts the natural nutrient cycling that keeps garden soil alive. Over time, the soil beneath fabric becomes compacted, lifeless and poorly structured.
It degrades and looks terrible. UV light breaks down landscape fabric within 3–5 years, even under mulch. As it fragments, pieces of black plastic become visible through thinning mulch — and removing degraded fabric is an unpleasant, time-consuming job.
Plants struggle to establish. New plants can’t spread their roots naturally through fabric. Perennials that should gradually colonise a border remain confined to their planting holes. Self-seeding plants — a key feature of relaxed, naturalistic planting — can’t establish at all.
Water distribution suffers. Despite claims of being permeable, many fabrics restrict water flow, especially once soil particles clog the pores. This can lead to dry spots under the fabric and waterlogging in low areas where water pools on the surface.
Where Landscape Fabric Actually Works
Landscape fabric has a legitimate role in these situations:
- Under gravel paths and driveways. This is its best use. Fabric stops gravel gradually sinking into the soil, maintains a stable walking surface and reduces weed growth on paths where there are no plants to consider.
- Under decking. Prevents weed growth in the dark space beneath decking boards where hand-weeding is impractical.
- Temporary weed suppression. On areas you plan to develop later (future patio sites, building plots), fabric covered with gravel keeps weeds manageable until you’re ready to use the space.
- Around widely spaced specimen plants. In a low-maintenance area with just a few shrubs or trees and no underplanting, fabric can work — but only if you accept the long-term soil health trade-offs.
Better Alternatives for Garden Borders
For planted garden borders, these approaches work better than landscape fabric:
Thick organic mulch alone. A 8–10 cm layer of bark mulch suppresses most weeds effectively without any barrier underneath. Top it up every 1–2 years as it breaks down. This is the approach most professional gardeners recommend — it’s simple, effective and improves soil health over time. Check our mulch calculator to work out quantities.
Cardboard under mulch. Cardboard gives you the weed barrier effect without the long-term problems. It blocks light for 6–12 months while slowly decomposing, feeding earthworms and adding organic matter to the soil. By the time it breaks down, the mulch layer above has established and weeds are suppressed naturally.
Dense planting. Nature’s own ground cover. Planting borders densely so foliage covers the soil leaves no light gaps for weeds. Combine with a bark mulch layer and you’ll have minimal weeding to do once plants mature.
Weed killer for persistent weeds. For tough perennial weeds like bindweed, Japanese knotweed and ground elder, no fabric or mulch will stop them permanently. A targeted weed killer before mulching is far more effective than relying on a physical barrier.
Already Have Landscape Fabric? What to Do
If you’ve inherited fabric in your garden or laid it previously, you have two options:
Option 1: Remove it. This is the better long-term choice but a big job. Pull back all the mulch, lift the fabric (cutting around established plants), then re-mulch with 8–10 cm of bark. The soil underneath will be poor initially — spread a layer of compost before re-mulching to kick-start recovery.
Option 2: Work on top of it. If removal is impractical, keep the fabric covered with a thick mulch layer and accept that weeds will root into it from above. Cut generous holes for any new plantings and feed plants well, as they’ll have restricted root access to the soil below.
Frequently Asked Questions
Does landscape fabric stop weeds permanently?
No. Landscape fabric blocks weeds growing up from below, but wind-blown seeds germinate in the decomposing mulch on top. Within 2–3 years, weeds growing on top of fabric are often worse than weeds in bare soil because their roots tangle with the fabric weave.
Is weed membrane the same as landscape fabric?
Yes — weed membrane, weed barrier, geotextile and landscape fabric are all names for the same product. There are woven and non-woven varieties, with woven being more durable but both sharing the same fundamental limitations in planted borders.
Should I put landscape fabric under bark mulch?
In planted borders, no. Bark mulch at 8–10 cm depth suppresses weeds effectively on its own, and the mulch benefits soil health as it breaks down. Under gravel paths, yes — fabric prevents gravel sinking into soil.
Is cardboard better than landscape fabric?
For garden borders, yes. Cardboard under mulch suppresses weeds for 6–12 months while biodegrading into the soil. It feeds earthworms, improves soil structure and doesn’t create the long-term problems that plastic fabric causes.
How long does landscape fabric last?
Quality woven fabric lasts 5–10 years before significant degradation. Cheaper non-woven varieties may break down within 2–3 years. Even durable fabric becomes less effective over time as soil builds up on top, and degrading fragments are difficult to remove from the soil.
Can I lay landscape fabric on top of existing weeds?
It will smother annual weeds, but perennial weeds like bindweed and Japanese knotweed will push straight through fabric. Clear perennial weeds with a weed killer first, then decide whether you need fabric at all — thick mulch may be all you need.
