4 Places You Should Never Use Landscape Fabric, Plus Better Ways to Stop Weeds

Landscape fabric is touted as an easy way to control weeds. This plastic fabric blocks weeds and reduces maintenance, goes the thinking. This may be true in the short term, but landscape fabric has some big drawbacks when used in certain garden situations.

For starters, it can suffocate the beneficial soil microorganisms that help make nutrients available to plants. It can contaminate the soil with microplastics when the landscape fabric degrades over time. Plus weeds will always find a way in, usually when they start growing on top of that sheet of plastic.

Landscape fabric can work for places in your yard where you never want to grow a living plant again, like under a gravel path or brick patio. Using landscape fabric any place you want plants to thrive is a bad idea. Here are the top places you should never use landscape fabric, and what to use instead to reduce weeds.

1. Your Vegetable Garden

A vegetable garden needs nutrient-rich, healthy, living soil to produce a big crop of tomatoes, bell peppers, and other veggies. Landscape fabric creates a barrier that can reduce your soil's quality in two ways:

• Landscape fabric suffocates soil. Healthy soil is alive with creatures, from earthworms to beneficial fungi, bacteria, and other microbes. They aerate the soil and break down organic matter into nutrients that plants can absorb. Landscape fabric compacts the soil, stops airflow, and cuts off the soil’s vital ecosystem from the rest of the world, leading to dead soil underneath.
• Landscape fabric blocks nutrients. You can’t easily add compost, fertilizer, or other soil amendments when a sheet of plasticized fabric is in the way. If you put straw, compost, or shredded leaves on top of the landscape fabric, the nutrients produced as that mulch breaks down won’t be able to reach the soil under the landscape fabric.

Alternative: Mulch your garden with a 4- to 6-inch layer of compost, shredded leaves, or straw to suppress weeds, retain moisture, and feed the soil as it breaks down. For more weed-fighting power, put down a layer of brown cardboard on the soil followed by a thick layer of compost or other organic mulch. Cardboard suppresses weeds but allows the soil to breathe. It’s also a great source of carbon, which feeds those all-important soil microbes.

2. Around Trees and Shrubs

Using landscape fabric around your trees and shrubs may keep the area looking neat and tidy for a season or two. But the long-term consequences for your landscape can be bad because:

• Landscape fabric encourages shallow roots. This happens because the landscape fabric traps moisture just under its surface, while the soil below becomes compacted and dead. The tree or shrub roots grow horizontally to use that moisture, instead of growing deep into the soil to anchor the tree or shrub. Shallow roots make the tree or shrub less stable in storms and more vulnerable to drought stress, a significant concern in an age of more extreme weather events.
• Landscape fabric causes root girdling, a condition where roots grow on the surface of the soil and around the trunk of a tree. This is because the hole you left in the landscape fabric for the plant becomes a constricting collar for the tree, girdling the tree and cutting off the flow of nutrients and water. The tree gets strangled by its own roots.

Alternative: Put a 3- to 4-inch layer of wood chips around your trees and shrubs. Keep it a few inches away from the trunk to prevent moisture buildup on the bark. This ring of wood chip mulch will suppress weeds, retain moisture in the soil, keep the soil cool, and build healthy soil over time as it decomposes.

3. Perennial Flower Beds

Perennial flower beds should evolve as plants grow and spread over the years, and gardeners divide and move perennials. Landscape fabric acts as a barrier that stifles this living, dynamic process.

• Landscape fabric prevents plants from spreading naturally. Perennials like hostas, coneflowers, and bee balm will slowly spread to fill in a flower bed. Landscape fabric blocks perennials’ underground rhizomes and above-ground runners from spreading, and it stops them from self-seeding.
• Planting and dividing becomes almost impossible. Dividing overgrown perennials or planting new ones is more challenging with landscape fabric in the way. Instead of just digging a hole, you have to cut through or pull up the fabric.
• Weeds will still grow. Wind-blown weed seeds will land in the mulch, on top of the fabric, and germinate. You’ll have weeds with roots woven tightly into the fabric mesh, making them harder to pull out by hand.

Alternative: A dense planting of perennials with a thick layer of mulch is the best weed control. Once the perennials are established, they will shade out most weeds.

4. On a Slope

Landscape fabric on a slope may seem like an easy way to handle a difficult part of your yard. However, it usually turns out to make the situation even more challenging for these reasons:

• Landscape fabric accelerates erosion. A heavy rainfall can wash over the surface of the fabric, sweeping away the mulch you carefully put over the landscape fabric.
• Landscape fabric makes it tougher for plants to survive in a difficult spot. Landscape fabric on a slope can develop pockets where water either pools or runs off before it can sink into the soil. Plants tend to get too little water, or too much.

Alternative: Plant hardy groundcover plants like vinca, liriope, or creeping juniper. Their roots will hold the soil and they’ll crowd out weed once established. Or use erosion control jute netting that’s biodegradable and allows plants to grow through it.