The Landscape Fabric Weed Barrier Myth

weeds growing through landscape fabric
Weeds growing through landscape fabric. Credit: UF Extension Escambia County.

I’ve seen it again and again. Helping a friend renovate their garden, I dig down a few inches and my shovel becomes entangled in a sheet of black plastic or some other material, collectively known as landscape fabric. Oh boy. Another case of pie-in-the-sky magic weed barrier.

“What’s this?”, I ask.
“Weed barrier.”
“Really? Then why are there foot-tall weeds in your garden?”

One of the great gardening myths is that landscape fabric will suppress the weeds in your garden for years. Sold under many trade names and made from an assortment of materials varying from plastic films to renewable sources, weed barriers are also sometimes impregnated with herbicides and fertilizers.

An experienced gardener learns that weed barriers defy logic, strangle plants, and decimate soil. Weed seeds largely move by air or animal and are deposited in the mulch or organic material on top of the weed barrier – mulch which doesn’t decompose as it should because the weed barrier doesn’t allow it to contact the soil.

Now to be fair, landscape fabric has its uses. It was developed for use in commercial agriculture and it’s highly effective in that capacity. But it’s less than useless in perennial home gardens and can actually do a lot of damage to your plants and soil.

The facts about landscape fabric as weed barriers

Weed barriers were developed for agricultural use, meant to be used for one season only.

In agricultural fields, especially those tended by hand, weed fabric is placed on top of the soil and the plants are installed through it, with an ample cutout so the plant can receive enough water and fertilization. Nothing is placed on top of the fabric so that water, fertilization, air, and gas exchange can take place. The fabric is in effect a mulch.

In home gardens, plant roots, especially of large shrubs and trees, become entangled in landscape fabric.

I’ve seen it often during renovations – roots of perennials spread across the top of the landscape fabric just below the soil surface or become entwined in the weed barrier. As a result, the roots don’t grow deep in the soil as they should. The root systems of healthy trees and shrubs must grow at least as wide as their drip line, and usually a few feet deep, but weed barriers restrict this growth. The lack of deeply penetrating roots make the tree or shrub easily toppled by high winds and very susceptible to drought. These pics from the University of Florida Extension service illustrate how landscape fabric girdles tree roots.

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Tough weeds most definitely will grow through weed fabrics.

Anyone who gardens where the mighty Canadian Thistle grows will agree – I’m convinced that thistle will grow through steel.

Landscape fabrics suppress below-the-fabric weed seeds the first season

…but seeds that later settle in mulch atop the fabric will germinate, and some will root. As the mulch level increases atop the weed fabric, and organic decomposition occurs, more opportunity for the rooting of weed seeds exists. Grasses like Nutsedge are a real problem – it will easily push through the fabric and the “nuts” (tubers) which are attached to the roots are virtually impossible to remove when growing underneath the weed barrier. And if you don’t get the entire nutsedge out, you get more nutsedge.

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Many of the old weed fabrics aren’t water and gas permeable.

I’ve frequently seen soil beneath and above old weed fabrics dry as a bone and compacted hard as cement, the color of baked clay. The shrubs and flowers were starving for nutrients and struggling to find water, slowly dying, even with layers of compost and mulch on top. And with little to no water penetration into the soil, or gas exchange at the surface, little soil food web activity takes place, which is immediately apparent by the distinct lack of earthworms and insects just below the surface. Conversely, when used in very wet or soggy areas, the weed barrier can trap water beneath it, creating a swampy mess.

Weed barriers separate the soil from the mulch and don’t allow for proper biological activity and drainage.

Mulch, compost, and anything else you place on top of the soil require actual contact with the soil to properly decompose. No decomposition means mulch gets moldy and becomes home to mice and other small rodents. And without decomposition there’s a lack of humic acids to feed the plants, insects, and microbial life.

Do weed barriers decompose?

I have unearthed nearly intact weed barriers more than 20 years after they were placed in a garden. So no, they don’t decompose in the time it would take for a material like burlap to decompose. In fact, many are guaranteed not to decompose for 25 years.

I never asked one, but I bet earthworms HATE landscape fabric.

Earthworms eat organic material, which they can’t reach through the weed fabric, so they crawl away in search of food. I have yet to see more than a few stray worms in garden soil underneath landscape fabric.

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Aesthetically speaking, when the weed fabric is exposed, it looks just awful – horrendous, ghastly, dreadful.

Did I mention how bad it looks when the mulch slides off?

Planting flower bulbs through landscape fabric is a pain.

To plant bulbs, you must cut a hole in the landscape fabric and plant it in the soil beneath. But animals that do their work below ground like gophers can sometimes push flower bulbs off the mark. If they do, there’s no chance that tulip or daffodil is going to grow through the weed barrier. And if you’re cutting holes in the weed barrier, you’re also allowing air, water and sunlight to get at weed seeds, so what’s the point?

Good luck dividing plants like geraniums and irises.

If you’ve tried, you know what I mean. What a royal mess. Most of the time, plants tangled in the weed fabric are a total loss.

Bad landscapers plant shrubs and trees with landscape fabric wrapped around the rootball.

I suppose they believe that the roots will grow through the material. They’re wrong. Roots will wrap around themselves inside the material, and it becomes rootbound.

So why do so many companies sell landscape fabric?

Because: a) it definitely has its uses in agriculture and b) it seems like such a good idea and so many home gardeners and bad landscapers keep buying it. 

As a gardener you have to accept the fact that there is no magic weed barrier (say it out loud, it’s liberating). Any mulch will do a far superior job to landscape fabric: stones, pea gravel, arborist wood chips, or yard waste. Layer it 2-3″ thick and very few weeds will get through it.

The best weed suppression and soil health is achieved by planting low-growing, native plants, especially ground covers. They easily out-compete weeds and cut down on the expense of buying and hauling mulch every year.

Sources: The landscape fabric myth from Linda Chalker-Scott, Ph.D., Horticulturist and Associate Professor, Washington State University;  Why I Hate Landscape Fabric, from North Coast Gardening; Garden myths: Landscape fabric-weed barrier cloth.

24 thoughts on “The Landscape Fabric Weed Barrier Myth”

  1. As odd as it seems, I use bug screens and put 2-3 layers on the ground, and then top it off with drain rock, lava rock, sand, pea gravel or bark mulch to stop weeds from poking through. I do not know, but suspect that, topsoil will not work. Rarely, if ever do I pluck out nasty weeds, after seventeen years. While others spend time picking weeds I do other things.

    I am no expert but garden stores liked my idea. Window screens permit air and water to go through to plants and flowers. We use window screens in our windows and am unaware of any concerns. Check it out with your garden experts and municipal headship for advice. We can possibly reduce, recycle and reuse stuff for other ideas and to think outside the box! The stuff I got was free from suppliers who were happy to get rid of rolls of new but defective fabric with tears and more. Good luck. Landscape fabric is costly, and will likely rot with soil matted to the fabric but you can draw your own conclusions.

    1. Kerwin: Thanks for your comment. On first glance, this would seem like a better solution, as it allows water and air to interact with the soil (and we’re all for recycling old materials). And the mesh will not interfere as much with decomposition as weed fabric will. However, you’re still going to have the problem of garden waste building up on top of the screens in which airborne seeds can root. I would guess that the materials you’re placing on top of the screens are doing more to suppress weeds than the screens themselves.

  2. Kris Abrahamson

    I have always suspected weed cloth was bad for the soil. Thank you for providing the evidence.

  3. Yep, I hear ya!

    I’ve used plastic fabric in the past and the weeds just push through it. Also tried thick newspapers and the water wasn’t getting through.

    My best results have been through solar sterilization. I cover the area to be planted with a heavy black plastic, and let it bake in the sun for a few weeks.

    When I lift the plastic the weeds are dead and the weed seeds no longer germinate. Well at least 80% of them.

  4. Do you have any advice for my situation? When we bought our house we spent weeks ripping out invasive ivy that had covered 1/3 of our yard. We tried to rip out the roots as far as we could, however we have been made painfully aware that the ivy is still there hiding underground. I foolishly put raised garden beds in near where some ivy had been and found that the ivy had come up under the beds and literally filled every inch of them with roots, smothering all the plants in there. You could barely get a shovel through it. I was going to try putting a double layer of the thickest weed cloth on the bottoms of the beds and try again, but maybe that won’t keep the ivy out? Maybe I should move the beds somewhere else? Also, I’m wondering if I should get rid of the dirt that was in the beds- do you know if ivy can regenerate from little bits of root? And I won’t use chemical weed killer, even if the ivy drives me over the brink.

    1. Angelina: Yes, Ivy can be quite persistent, as you’ve learned. Do not put weed barrier under the raised beds, as that may reduce the ability of the bed to drain after heavy rain, defeating the purpose of the bed. Yes, Ivy can regenerate from small bits of vine. yes, moving the beds is an excellent idea, but if you do so, fill them with new soil and compost. If you want to keep the beds where they are, try soaking them with a white vinegar solution to acidify the soil and discourage the ivy growth. However, you’ll have to wait a season before planting vegetables or most fruit, as they won’t do well in the acidified beds.

  5. I have used pro five landscape fabric on the hill behind my back yard. I live in the foothills of Northern Utah and am inundated with scrub oak. It grows horizontal toward the house to get to the sun light as the hill faces the southwest. I try to kill and cut down as much of the runners as possible, but it is just impossible to keep it out. The area is behind a rock wall and we like to keep it ‘natural.” I have used weed barrier cloth with quite a bit of success. I don’t want anything but the wild choke cherries, wild roses and the few pines that I have planted to grow. I put natural shredded mulch on top and it keeps the weeds and scrub oak from growing out of control. I think there is a place for weed barrier, but definitely not in your garden area where you have ornamentals.

  6. Todd, we recently removed all the turf from our front yard and replaced it with drought tolerant native landscaping. Unfortunately, within a few weeks nearly our entire yard has been over run by yellow nut sedge and purslane. Our new garden has no weed fabric and lots of ground cover, yet the weeds have pushed out the desirable plants and killed most, if not all, of the ground cover. Given the severity of the situation, what other options do we have other than installing a weed barrier?

    1. Michael: Renovating a garden or landscape always poses challenges like this. When we tear up existing plants and replace them with new, much smaller varieties, we leave lots of space for “weeds” to take over. Plus, during a massive planting like yours, we expose lots of weed seeds that never received light and water before. It takes some time, at least 2 seasons for the newly planted landscaping to establish itself and start growing and covering those “opportunities” for native weeds.
      First of all, you’ll need patience and elbow grease. A weed barrier is not the solution, as it will restrict the natural growth of the new plants and especially the ground covers, as they must attach directly to the soil. You’re going to have to be diligent for this season and next, and pull or otherwise remove weeds around your new plants. If your property is large, invest in a Stirrup Hoe like this one, which makes weeding a breeze – you just keep cutting the tops of the weeds off, little bending or kneeling required.
      Next season, and season by season, fewer weed seeds will be exposed to the elements, and as your new plants grow in, they’ll shade and cover more area. Eventually, they’ll be packed tight in there and few weeds will have the opportunity to sprout.
      Hang in there!

    2. If weed barriers were so useless why do they sell. I’ve tried mulch alone around decorative islands of ornamental trees and/or plantings, and quickly they become infested with unwanted grass, weeds, etc., that are difficult to pull through the mulch without bringing a mess of soil with it that mixes with the mulch.

      There is a 10th of the growth -and work weeding- with a weed barrier. The unwanted growth’s root is better contained by whatever small puncture it makes in the barrier sheet, and easier to pull with less disturbance to surrounding areas.

      However, I’m not inclined to use barriers with flower beds: They are difficult to lay and make it a chore to add or remove plantings. I usually clump plants , add ground cover and mulch, giving weeds much less ground space to make themselves known.

      1. Ron: I would encourage you to read this pdf from Linda Chalker Scott, a professor of horticulture at the University of Washington: https://puyallup.wsu.edu/wp-content/uploads/sites/403/2015/03/landscape-fabric.pdf. In it she says,
        1. Geotextiles degrade in the landscape in as little as one year if unprotected from sunlight.
        2. Any organic matter or soil on top of the fabrics will hasten their colonization by weeds; this precludes covering the fabric with anything but inorganic mulch like pebbles. It also requires
        continual maintenance to keep the fabric free of debris.
        3. Weeds will eventually grow on top of and through these fabrics, making their removal difficult.
        4. Landscape plant roots can also colonize fabrics, and they are damaged when the fabrics are removed.
        5. The aesthetic quality of landscape fabrics is minimal; it becomes worse as the materials begin to degrade.

        1. Hi-
          I can’t argue about the environmental effect of ground covers but they still have saved me considerable time spent pulling weeds, and worse, grass. Two areas treated with ground cover then mulch have been reasonably weed free over the years. My flower beds, where I have not followed my own advice of supplementing heavily with only mulch
          and ground covers, are ( excuse the pun) a hot bed mess of every imaginable , unwanted growth.

          I recently planted hostas in a backyard area, seldom seen and never used. Most of the day the area is cast in shadows. That too is protected by fabric ground cover, which will soon be covered with 3/4” natural stone, as the yard has farm elements, such as a rustic section of fence, vertical board and the suggestion of a loft door ( a design solution to disguise an eyesore patch job of badly fitted wood panel).

          The land has a slight slope. It will be interesting to see if the semi-impermeable ground cover creates troughs of water culminating in a spectacular waterfall over a concrete retaining wall spilling onto a dugout patio area, accessible from a lower level French door!

          BTW…the lower patio area, once covered in a haphazard layout of commercial brick – much of which is turned on its side, allowing a measure of needed drainage, since the brick has slotted holes- and small planting areas, will also get the weed barrier and stone treatment. I’m trying to anticipate what , if any, pooling of water could occur. I could have an unintended water feature.

          Thank you, anyone who’s patience held up through this opinion. Any suggestions are welcome.

  7. My question is how do you remove the black fabric ? We just moved into a house with landscape fabric laid in all of the beds around the house, and I can’t plant anything. Should we scrape all the mulch to one side, cut the fabric and pull it up, then re-mulch the beds? It’s very tough and hard to cut.

    1. Susan: You have the right idea. Whatever is on top of the fabric has to be removed. If you’re keeping any of the plants in the bed, cut around them before pulling up the fabric and watch for roots that have become entangled in it. Work very carefully around the plants, because if they’re entwined in the fabric, you’ll have to work to free them from it. After you pull it up, I highly suggest adding a few inches of finished compost, because the plants are probably starving for nutrients, as is the soil. Then add mulch on top – the old stuff (if organic), or new if needed.

    2. Hi- Weed barriers are hard to cut! Forget scissors. I use a sharp utility knife and keep handy a lightweight piece of plywood, slightly wider than the roll of weed barrier. Roll out the approximate piece you need over the area, mark, then cut across on board. Better to overestimate the length because it can often be folded under for the area you plan to use it.

  8. “These pics from the University of Florida Extension service illustrate how landscape fabric girdles tree roots”

    No, they don’t—they demonstrate the desirability of removing synthetic burlap from the root balls of saplings before planting. See:
    http://hort.ufl.edu/woody/bb.shtml

    A very different situation…

  9. I LOATHE the stuff! Especially since the former owners of our current house thought it’d be super fun to use double layers of it around the entire house/in every bed and then use ROCKS as mulch. Like, thousands of dollars worth of rocks. Of course they also thought astroturf glued to the front porch and steps was cool.
    (Anybody need some rocks?)

  10. Henrietta R. Harding

    One of the biggest barriers to organic gardening success, and I mean that literally, is landscape fabric. Any kind of fabric or plastic that keeps weeds down will also keep fallen leaves or mulch from adding organic matter to your soil, leaving behind a hardened, dead zone where plants struggle to survive.

    1. Same with my mother, having spent all her life gardening she kept saying the same. My sister, being a proud young owner of a house and garden was trying to explain her these were the modern methods of gardening when my mom said it was bulls..t. Now she can herself that see mom has been right but you know how it is about mothers and kids – mothers cannot know better than landscapers. So, going to send this article to my sister 🙂

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