Using carpet to stop weeds

Question

I've got these citrus trees in my back yard but they're surrounded by weeds (5 foot high). The garden bed is elevated and hard to mow.

I also have this old carpet just waiting to be thrown away.

I'm thinking about weed whacking the weeds and then laying the carpet over them to stop them coming back, then covering it with pine bark.

Long term, is this a good way to deal with weeds?

don't let the carpet (or whatever weed barrier you end up using) and the mulch layer touch the trunk of the tree, start about 4inches (100mm) away from the trunk... — Mike Perry, Commented Sep 7, 2011 at 18:08

bstpierre · Accepted Answer · 2011-09-06 12:07:25Z

It might be a good way to deal with weeds, depending on what plant you're dealing with, and what the carpet is made of.

Dealing with the carpet first:

If the carpet is natural fiber, then it can do well as the bottom layer of a sheet mulch, which is basically what you're proposing (you're talking about two layers instead of 4). In this case, make sure you cut the weeds as low as possible -- you don't want them to try to regrow once you've covered them. Since the carpet fibers are natural, they will break down over time. The pine bark will also slowly decompose. You will want to renew the upper layer regularly to keep weeds controlled.
If the carpet is petroleum based (e.g. plastic backing), think twice before putting it on your soil. It will take a long time to break down, and may contaminate your soil with chemicals that are hard to get rid of later on.

And then thinking about plant type:

If the weeds in question are "simple" annual or perennial weeds (e.g. dandelion, crabgrass) that spread by seed (i.e. they don't have spreading roots / "creepers"), then this control strategy should work well.
But if they spread via the roots (e.g. creeping charlie, leafy spurge) then they will probably just spread underneath your barrier until they poke out one of the boundaries of the carpet. In this case, you will have moved the problem, which may be all you need -- to keep it away from your trees -- but it could cause other problems, depending on where the weeds migrate.

So before you go to all the effort of laying down the carpet and spreading bark mulch, you should identify what kind of weeds you are dealing with.

@Coomie - If you can get hold of a bunch cardboard, or a lot of newspapers, you can take the same approach. Make sure to overlap the sheets, and if you use newspaper, use several sheets for a layer. — bstpierre, Commented Sep 7, 2011 at 2:56
Long term should I look at planting some spreading ground cover? — Coomie, Commented Sep 8, 2011 at 1:42
Unfortunately I don't have a good answer to that. Anything vigorous and spreading enough to choke out weeds has the potential to become invasive in its own right. Less invasive ground covers may still allow weeds to grow up through the cover. The one thing I have had luck with is low growing white clover -- the trick is getting it to grow thickly and become well established so that it completely dominates the area. But my luck here is just that -- luck -- I can't say for sure what variables caused my success. — bstpierre, Commented Sep 8, 2011 at 2:38
Perhaps I'm better off pulling out all the weeds and planting some clover... — Coomie, Commented Sep 8, 2011 at 2:48

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