Key Points
Plastic weed barriers suppress weeds initially but become problematic over time.
Watch for the easily detectable signs that your weed barrier is failing you and take action to replace it.
Alternatives to weed barriers include tighter plant spacing and the proper use of mulch.
Plastic weed barriers (including landscape fabric) have been popular with gardeners for decades. But some gardeners are starting to question the efficacy of plastic weed barriers.
They may work well in the short term, but are they really a good long-term solution to pesky weeds? And even if they do get the job done short-term, do they cause more problems than they solve?
We checked with some experts to get the lowdown on everything plastic weed barriers.
Meet the Experts
Dan Sekowski is the associate director of outdoor landscapes at Longwood Gardens.
Mary Phillips is the head of native plant habitat strategy at the National Wildlife Federation.
Not a Long-Term Solution
The idea seems sound enough: You even out the soil, lay weed barrier down, make cuts to install plants, and cover with bark mulch. In the short term, you won’t have any weeds.
“While they may suppress weeds initially, they often fail over time,” says landscaping pro Dan Sekowski.
As time goes by, the mulch will break down and organic matter from fallen leaves will intrude, opening the door to weeds.
Soil Disruption
Credit: Photo courtesy of Natural Resources Conservation Service Soil Health Campaign
Weed barriers are exactly that: a barrier. Yes, they can keep weeds from popping up, but they can also keep helpful, organic materials from settling down.
“Organic mulch is meant to break down and feed the soil. Fabric interrupts that process, preventing natural decomposition from improving soil structure and fertility,” says gardening expert Mary Phillips. “Instead of building soil, you often end up slowly degrading it.”
It will be clear enough when you have this problem: Your plants will begin to perform poorly.
Water and Oxygen Disruption
Phillips also contests the notion that weed fabrics are as breathable as they’re advertised to be.
“Some landscape fabrics are thick, restricting water and oxygen flow to the soil below, which can stress plants and affect long-term health,” she says. “In thinner fabrics, soil and debris can accumulate above and reduce permeability.”
One sign of this problem will be plant foliage wilting on hot days.
They Don’t Break Down
Credit: The Spruce
“Because most landscape fabrics are petroleum-based, they do not truly break down,” Phillips says. “Over time, they can fragment into smaller pieces that remain in soil, creating long-term cleanup challenges and introducing unnecessary synthetic material into garden ecosystems.”
Difficult Maintenance and Removal
As weeds eventually become established in the planting bed in spite of all your efforts, their roots make contact with the plastic weed barrier. This makes for a maintenance nightmare.
“The fabric becomes tangled with roots and hard to remove,” Sekowski says.
Even if you are not interested in removing the weed barrier, this still creates a problem. Pulling the weeds will be more difficult with their roots anchored in the plastic weed barrier.
What to Use Instead of Plastic Weed Barriers
Weeds can take over a planting bed quickly if left unchecked. The result is both an unsightly landscape and hard work for you.
But giving up plastic weed barriers doesn’t mean giving up on weed control strategies altogether. Here are some effective alternatives to plastic weed barriers:
Groundcovers: Perennial groundcovers keep sunlight from reaching weeds, controlling them naturally. Try Aubrieta, Campanula, Thymus serpyllum, and Phlox subulata for full sun, or Ajuga, Leucothoe, and Hosta for shade.
Mulch without the weed barrier: “Use 2–3 inches of shredded bark, leaf mulch, or compost,” Sekowski suggests. This suppresses weeds naturally, improves soil structure and moisture retention, breaks down over time, and feeds the soil.
Sheet mulching: “Sheet mulching, using cardboard and mulch selectively, is useful for initial bed establishment without introducing long-term plastic,” Sekowski says.
Proper spacing: Weeds compete with your plants for water, nutrients, space, and more, which suggests another alternative: simply eliminating as much space between your plants (even non-groundcovers) as possible to crowd out weeds.
Read the original article on The Spruce
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