Weed Barrier Is Not What You Think It Is

by Ben Bowen

Weed fabric. Weed cloth. Weed barrier.

Landscape Weed Cloth

Whatever you call it, the idea behind installing it is simple:

Cover the ground with weed barrier fabric, put mulch or bark dust on top, and never worry about weeding again. Or, if you fancy yourself a realist, cut down drastically on the amount of work needed to take care of weeds.

Here is the problem: weed fabric rarely works and is often a really, really bad idea. This raises some questions:

Why doesn't weed control barrier work? When can it be an option? How should it be installed? And what other options are there for weeds?

Why Weed Barrier Fabric Doesn't Work

Weeds are a huge issue here in Portland. Our spring weather seems tailor made for them. Cracks in the sidewalk sprout weeds in April! So it shouldn't come as a surprise that a roll of fabric is not going to cure the weed problem.

Here is what happens when you install weed barrier:

Weeds grow in the bark dust that you put on top. Weeds grow in space where two pieces of fabric overlap. Weeds grow in the holes you cut for plants. Weeds grow where your fabric meets the sidewalk.

And guess what... the weeds are now harder to remove. When you pull a weed out that is rooted below the fabric you will probably pull the fabric up. Or the fabric will hold the roots in place making it difficult to get to them.

If you use a hoe to chop weeds out you will snag the barrier and pull it up. The same thing happens when you rake weeds up after pulling.

There are other difficulties:

If you have any slope or unevenness to your yard guess what happens when it rains? Bark dust slowly washes off the high spots until it exposes the fabric. Ugh.

And the next time you decide to renovate the landscape? You will be paying someone to rip that fabric out!

When Should You Install A Weed Fabric?

For all that, weed cloth does have a use: under hardscape.

It may be bad under bark dust, mulch, soil, or compost but it works very well under river rock, gravel, decomposed granite, or flagstone. In fact, Ross NW Watergardens typically uses it under these materials. Why?

It certainly does help with weeds, but it also keep mud and aggregate separate during our wet winters!

How Should Weed Cloth Be Installed?

When installing a weed fabric under gravel or other stone product, keep these pointers in mind:

  • You will likely need to remove 3"-4" of soil, then install the fabric, then install your stone. If you install the fabric too close to the surface you will end up seeing it as everything settles.
  • Use a high quality material. We use this brand of landscape fabric from Ewing Irrigation.
  • Anchor the edges to the ground with landscape staples.

How Else Can Weeds Be Controlled

But if you can't use weed control cloth, what can you use to control weeds? Here are some ways to manage them long term (cause you are a long term kind of person):

  • Pull them every 1-2 weeks from March 1 - December 1. That is a reality of maintaining a landscape here in Portland. Don't let them get out of hand and you will never have to spend an entire weekend, just an hour here and there.
  • Pay someone else to pull them every 1-2 weeks.
  • Plant ground cover. As these plants mature they will grab most of the sun and water, leaving little for weeds.
  • Lay bark dust. The Ph of bark dust is not conducive to weed growth, at least for 3-6 month.
  • Convert more of your landscape to hardscape. Create more gathering space, dry creeks, pathways to lower the areas for weeds to grow.

When it comes to weeds there are no shortcuts. It will take planning and work (or hiring someone) to minimize the time it takes to get rid of your weeds. Need help planning? Reach out to a designer today.