Cement guard against weeds

[Jim Butts]

I have a quarter circle garden in my front yard with one side against my driveway and the other against the sidewalk. It contains white rocks with a little juniper bush in the center. This garden is always full of weeds and I'm not the type to do the work needed to keep it weed free.

Last time I was fed up, I removed the rocks from the garden and then laid down black matting which is supposed to block weeds. On top of that I put mulch and then added white rocks on top. All that work did not prevent weeds.

My thought this time is to remove the rocks and mulch and pour in concrete - maybe 2 inches thick. Then I can put the white rocks on top without the mulch.

I am concerned for the plant in the center. I will want to leave a hole for the plant. My concern is that the plant would be starved if I don't make the hole big enough. Would the plant do fine as long as its root system can dig down under the plant or would I need to give it some breathing room?

[Steveo]

I use a low pressure roundup application 2 or 3 times every growing season, along with a spring pre-emergent, on the areas I don't want to string trim. Works in the beds too. Nothing is failsafe.

Won't that just give you something else to trim around? ;)

I'd suggest moving that plant. Sounds like it's in the way.

[Colbyt]

Jim,

I think if you remove the rocks and lay down landscape fabric, the dark gray stuff sold everywhere, and then add the rocks on top of that you will be fine for 5-10 years. Last time you added mulch which provided an organic base for stuff to grow in.

[Chet Hayes]

I agree. Putting mulch on top of the fabric defeats the purpose. The mulch decays into organic matter which weeds will grow in. The fabric alone should solve the problem. If an occasional weed does sprout, a quick spot treatment with roundup a couple times a season should fix it. Or, as was pointed out, you could also put down a pre-emergent, but that shouldn't be necessary.

Cement is a poor choice for a variety of reasons. Where is the rain water going to wind up? Plus, if you decide to make landscape changes, having concrete all over the place is going to be a real problem, even if you just want to add a couple of bushes.

[Jim Butts]

First off, I was wrong about the mulch. I did not put mulch on top of the weed barrier.

And some replies to comments...

Why would I want a garden with no plants?

I have probably misused weed barriers in several situations by replacing a small amount of dirt on top. I find that grass has no problem forcing its way through the barrier. Perhaps if I bought a lot and put down 12 layers of the stuff, it might work for 5-10 years.

The area is only about 3-4 feet across. Why would cement under the rocks keep water from draining considering the small area of the quarter circle? And I do not have plans to put more plants in such a small area nor do I plan on increasing the size of the garden.

Finally, the garden is right next to a sidewalk and children have a habit of picking up a rock from the garden. I do not plan on chasing down the parents of every child that does this and accept the fact that they are just being children. It does make me hesitate spraying poisons on the rockbed.

I suppose early next spring I could try the weed barrier again. This time I would put down multiple layers and nothing on top but rocks. I would still have problems around the rim of the garden which would require chemicals to kill encroaching grass.

[Steveo]

A cement garden? Here's what you posted.

[Chet Hayes]

Water can't drain through concrete. The point is, even if it's only 4 feet wide, the concrete needs to be pitched to take the water somewhere where it can drain. For example, a typical situation would be to have a sidewalk which is several inchs higher on one side of a bed and the house foundation on the other. Concrete this over and you need to figure out where the water is going to flow and how it should be pitched. If there is a downspout nearby, it only gets worse. You can easily wind up with a small pond pooling water up against the foundation where it will cause problems, particularly through freeze/thaw cycles.

And to top it all off, eventually, organic material is going to make it's way through those rocks and wind up on top of the concrete. Small dirt particles blow in with the wind, small leaves decay, etc. When enough accumulates, you're back to having at least some weeds grow anyway.