You can add more paper and mulch. Or you can use roundup to kill whatever is coming up. It may take more than one application, depending on what's growing there.

I believe clear plastic works better than black if you want the soil to heat up. This will kill weed seed, pathogens, and microbes in the top few inches of soil. If you dig in it later, you will bring more weed seeds to the surface where they will germinate, so if you disturb it, mulch it right away to shade out the weeds.

I think you might have been working with the false assumption that this - or anything - would be a permanent solution. But weed seeds blow around, and they land in and grow in mulch. On the up side, my guess is that the weeds you have now are less deep-rooted and less entrenched than the ones you had before (unless it was stuff like blackberry that is now growing through the paper, of course). So this time control will be easier.

What will reduce the weed population over the long term is (a) ground coverage by more desireable plants, and (b) vigilance. Even your beds, once you get them established, will need regular weeding for a long time, whether from the old weed seeds in the soil, or from new seeds blowing in. As your plants cover more ground, fewer weed seeds will germinate. This is why starting huge swaths of planting beds at once is not such a good idea - one new area per year is best, whatever amount of weeding you can keep up with.

Also keep in mind that it is now getting a bit too hot for new planting. You might focus on weed control for the summer, and then plant in fall.

KarinL

What were you planning to do once you had the paper and mulch down? As Karin says - that is just the first step.

The newspaper rots away. The mulch will also, but slower. If left alone it will always revert to weeds.

We had a very thick, established cover of Bermuda grass around our joshua tree that we wanted to get rid of. If sprayed with roundup it would have taken a lot of applications over a considerable period of time because with the extensive rhizomes underground it would resprout (found this out the hard way). That would have been a lot of spraying so we went the plastic route.

First in our backyard we had tried soil solarization with clear plastic in a previous summer. It gets very hot here but it acted as a greenhouse and the grass grew profusely under it. So in this joshua tree corner we watered the area well in the spring and covered it with black plastic to exclude light. After a year when we pulled it off sure enough a lot of dead grass that has only sprouted back in a couple of spots.

That black plastic is as ugly as all get out though, putting mulch on top sounds like a good idea.

Maria

mohavemaria--the black plastic works...but I HATED it when my next-door neighbor used it. Not because of the aesthetics...but because of the MOSQUITOES. Yes, the rain water that puddles in the plastic stays there long enough here in NC for the tiger mosquitoes to use it as a nursery.

Probably not an issue where you live--if I sussed out your user-name correctly!

melanie

I'd like to add that I had a similar problem when I started working on my yard 6 or 7 years ago, only it wasn't just a side hill filled with weeds, it was that AND the whole rest of the property. I'll tell you the story and maybe you can get something of value from it:

Of necessity, I did what Karinl said and it has worked well, even if it has turned out to be a lot of effort (but what worthwhile endeavor doesn't take real effort?). I picked one part of the landscape -- the front yard -- and mentally sectioned it into chunks and weeded, amended and planted small areas at a time each year until I thought it was presentable, if not truly finished.

Meanwhile, each year I either bought mulch or collected leaves and trimmings from neighbors and MADE mulch (can't afford to plop a lot of money down) and completely covered the back and side yards to keep the weeds down until I had time (and money) to address those areas (we have a lawn-less yard -- it's all either mulched or planted). I've never used any kind of physical barrier between the soil and mulch. I DID end up Round-uping the side yard several times in the past few years because the weeds there were more persistant and stubbornly grew right through a 5-inch layer of mulch; but otherwise, I've definitely learned the value of thick mulch and a scufflehoe. Also, the years of mulching the side yard have improved the soil there tremendously, and now that I've addressed both the front and back yard, the side is in excellent condition to start on.

The end result is that the amount of weeding I have to do now is minimal (and it was never overwhelming to begin with because I've been working small sections at a time) and I have a real landscape (except for the side yard, which I have yet to begin -- but it's mulched!). I highly recommend the "divide and conquer" approach. And since it's a grass-less slope that you're working with, don't overestimate the value of collecting leaves from your own and neighbor's yards to mulch with and help improve the soil -- it's like magic!

And as was hinted at earlier, short of laying down concrete, there is no such thing as a permanent solution in a landscape. You'll have to do some kind of maintenance every growing season -- that's just the way it is.

Sorry for the book. Hope it helped.

Unfortunately, the 5 sheets of newspaper is not sufficiently thick to smother any undegrowth. Generally the recommendation in this type of situation is at least a section of about 1/4" thick. And thicker won't hurt. The mulch is generally used to to hold in moisture to help the newspaper breakdown and to prevent it blowing away. And depending on the mulch used, seeds can blow in and more weeds develop, but as mentioned, these are relatively easily pulled.

I'd try again, this time with a much thicker layer of newsprint (or even cardboard) under the mulch. If you want to go to the additional expense, you can always apply a herbicide (like RoundUp) first, then start applying the layers. During the growing season and the heat of summer, results will be faster than if you tried this method in fall. I wouldn't contemplate any permanent planting until that time, so have you have plenty of time to determine how and with what the slope will be planted once the existing vegetation is destroyed.

Solarizing the soil with plastic is an option, but for best results, you cannot cover it with mulch - this defeats the interaction of the plastic with the sun generating high enough heat to kill the undergrowth. Solarization also destroys the soil biology, which is never a good thing and will not be an issue with the newspaper/mulch combo.

Try searching under "lasagne gardening" for more information on this method.