I would rake any existing mulch aside, cover with newspaper/cardboard & put the mulch back. I prefer shredded. Nuggets take too long to decompose and move around too much.

I think newspaper/cardboard is a great idea. I also do that in problem areas with problem weeds that are particularly ... well ... problematic. :)

When it comes to newspaper, I find that a layer of about 6-8 sheets thick underneath the mulch works great. By Fall or next Spring you'll probably find the newspaper is pretty well decomposed enough to simply be dug into the bed with compost. No worries and no need to worry about newspaper print/toxicity. That's been covered a few times already here on the forums and word is that it's OK.

ps - My plants prefer the New York Times. Although some of those tropicals can really get into more trashy papers like the Post. Yikes!

As a gardening newbie 25 years ago, I used landscape cloth once. It turned out to be a big pain! It doesn't decompose, prevents organic material from breaking down and nourishing the soil underneath, makes it difficult to transplant or move plants, and the roots of plants (and weeds) grow into the cloth. And ironically, it doesn't even stop weeds for long because organic debris builds up on top of the landscape cloth and weeds will germinate and grow down through the cloth. And what a hassle to remove!

Newspaper or cardboard make a pretty good weed barrier - not sure if they will work with your invasive grass however. There are apparently some grasses (like Bermuda grass) that are really difficult to control.

solve your problem.. then mulch ...

i suggest roundup ...

is its already got you cussin like a marine.. so let me suggest that some layers of newsprint is NOT going to solve your problem ... in fact. i bet a 12 inch layer of concrete.. will only slow it down enough.. until it grows out the edge ...

if it were me.. build a new 'holding' bud.. move everything out of this one .. insuring all grass is out of the plants ..... apply roundup ... and in fall.. move everything back into the bed ....

mulch and paper will not kill nor slow down grass.. IMHO ...

ken

We started putting newspaper down around some of our plants,
then used cyprus mulch......
Although its not 100 percent effective, it sure has
cut down on our weeding .
In the larger beds where we grow dahlias and zinnias,
i put newspaper down then wheat straw.
Our grass is fescue blend,but we always fight bermuda
by applying roundup where we can and just pulling out
where we can .

carol

If twitch grass is the same thing as 'quack' grass, I feel bad for you. We had such a problem with it in our initial 25 x 25 foot vegetable garden, that I stopped trying to grow vegetables there for a few years. Pulling it out didn't help, mulching while still growing vegetables didn't help and being new to gardening, I tried rototilling it and that made it much worse. Just multiplied all the little pieces of roots.

Since I grow organically and it was a vegetable garden, I did not want to use chemicals. Once I was ready to try again, we used a very large piece of clear plastic left over from an ice rink and left it over the entire area for a full year. Just anchored it with rocks. We got lucky it was dry and hot that year and it baked it right out of 90% of the soil. We still had a little on the shady edge of that patch, that I still have a problem with.

I would be VERY careful of moving any plants from that area to other parts of your garden. If you can be reasonably certain that you are not digging up roots of the grass with the existing plants, and you really want to save some, I would pot them up and wait and watch for grass to sprout before moving them. If you can instead wait for seed and save it and start over that would be better. If you have the same plants in other parts of the garden that you can divide, better.

Of course I can't say that a thick layer of cardboard and thick layer of bark mulch, won't do the trick if you abandon the area as a perennial bed for the same amount of time. Newspaper, I doubt will work.

Not talking about a single layer of newspaper, but at least 8-10 sheets thick, held flat to the ground with several inches of mulch. Overlap the edges by at least 6". It works on the bermuda here, so I don't see why it wouldn't work on other grass. If the grass is rhizomatous, I would use a shovel to sever it at the transition between lawn and bed. If there is not a barrier edging (both above and below ground) the grass will creep back in. If you start digging holes through the paper before the grass is dead, it won't work.

Thanks very much to all of you. Yes prairiemoon quack and twitch grass are the same thing. I solved the problem in my veg garden some years ago by growing in seversl raised beds instead of the original 40'x 40' bed. Every year I lost several inches around the perimeter of the bed. All of you have given me food for thought and I will use the info to come to some sort of battle strategy. I really think I must be more vigilant about pulling it out the moment I see it. As much as I hate using chemicals, I may use some Roundup along the edge. Maybe several layers of the National Enquirer would discourage the roots. LOL

If you are considering any kind of bark/wood mulch, you may want to read about the fungus problems it can cause. Don't know if this would be a problem in your area.

Here is a link that might be useful: Artillery fungus from wood mulches

This year is the first time I've heard of this artillery fungus. I'm sure the linked article is authoritative about this stuff, but I question the wisdom of some of the advice, like suggesting one put black plastic topped with rocks without mentioning that this would probably kill whatever is growing in the "mulched bed" and would be the end of gardening in that spot.

I also got quack grass in my flower bed,my daughter clean it up alot and then she used roundup protecting my lilies after they bloom we will move the bulbs and do more spraying and hope to get rid of it., Good Luck to us both

When overlapping cardboard is utilized under mulch to keep down the weeds, how does water percolate down to the roots of the plants? WOuldn't you have to really keep the area well wetted to get the cardboard to break down enough to let water through?