Sorry, it won't work, in any of your proposed iterations. Because you can not (will not?) use glyphosate (Roundup tm) or other chemical to kill everything that's there, everything that's there will remain there. Period. You can roto-till, scrape, dig, and pull. But there will always be propagating remnants of seeds and stems that will overgrow things once again.

Heat works, but this is now fall and winter. No chance for that under any kind of mulch now. Summer sun on black plastic, for an entire season, does a number on seeds, stems, and roots. It works, but that's for next summer.

In short, you will have to take an entire growing season for site preparation. And you would have to do that with glyphosate, too. In short, there is no quick way to eliminate the junk stuff that will malignantly overtake anything you desire to plant in your scheme.

One of the worst things would be to bring in "new dirt." You must remember that at night there are little unseen weed seed faeries that sprinkle the worst weed seeds on every square inch of exposed soil. Your brought-in new soil will be loaded with weed seeds you haven't even seen yet. The only way around that is to have the soil sterilized in a pressure cooker (really).

Sorry for the bad news. But there is no easy way to create a "wildflower meadow." I do this professionally and have encountered all of this.

One other point. Even if you go to all the effort of proper site prep and you plant your wildflowers, in two or three years you will be very disappointed. Wildlowers never exist in the wild in the absence of supporting and weed-suppressing grasses. You need to add appropriate grasses to your mix if you want your landscape to last more than two or three years.

Lastly, you will also have to properly burn or mow everything each year after establishment. Just to let it grow will be to taunt the weed seed faeries and in the end you will have a giant patch of horrible weeds, not the wildflowers you envisioned.

The real problem (you are starting to get the picture, I think) is that there really isn't such a thing as a wildflower meadow -- at least one that can be artificially created. Your better effort would be to restore a native herbacious community. Here in the Midwest, that's a native prairie, of course. You'll have to consult some Georgia native plants experts to see what works down there. I know some good work on this has been done in the Atlanta area by some professionals. Look into it.

But for now, go back to the drawing board.

Greetings. This obviously isn't going to be easy, but at least there are good ideas and resources out there, like Gardenweb! So thanks for your suggestions...back to the drawing board indeed ; )

The problem is mainly that you mentioned bermuda grass. I used smothering + topsoil in several places where I did not have bermuda, and they worked well. One I had already plugged a little but the area was just so hopeless I started over smothering it.

I also used a LOT of roundup for the main lawn/meadow and I still have some bermuda that I'm spot treating. However I will say that spot treating works wonders. The little bermuda sprout wants to send sugars to all the rhizome under your cardboard. 2-3 sprays of glyphosate no more than 5 days apart will kill a lot of what is underneath too. I find it very satislying. :)

Heavy cardboard and mulch (compost + dirt) might work if you are vigilant. Make sure you:

EDGE the area. (I kill off bermuda sprouts in the bark edging area still)
Seriously overlap the cardboard.
Wet the cardboard completely, and drape wet newspaper over the seams before tossing on topsoil.
Keep a spray bottle of glyphosate on hand and expect to spot treat!

For a 25x30' yard this is quite doable, but you have to be prepared to patrol for bermuda. By importing topsoil, you reduce the weeds dramatically, and this would make the bermuda more obvious. Appliance stores are a great way to get large sheets of cardbard -- the fewer seams the better. Any rips should have a LARGE piece placed under them when you lay the cardboard.

I redid my backyard this way. I used edging (had to put in pathways anyway) and a combination of cardbard/wood mulch with newspaper/dirt in areas without too much bermuda. Also, doing this NOW when it's winter works best. The cardboard/mulch or dirt smothers the bermuda and it does in fact rot because of this. The areas with I did before last winter had almost no bermuda pop up. The areas done during the summer had a lot more bermuda persistence.

CJ

Here is a link that might be useful: battle against bermuda

One of the worst things would be to bring in "new dirt." You must remember that at night there are little unseen weed seed faeries that sprinkle the worst weed seeds on every square inch of exposed soil. Your brought-in new soil will be loaded with weed seeds you haven't even seen yet. The only way around that is to have the soil sterilized in a pressure cooker.

^^^^^^^^
in the long run...that is ur worst prob.

i find that copious amounts of roundup over 1 year really does the trick most effectively. not turning the soil will keep what is under, under.

and ur spot treating of remaining nasties is also the answer. wet cardboard and other 'smothering' is a whole lot of work with very little results.

john gives good advice :)
now if has a trap for those fairies...i wanna hear about it

froggy

I don't know. Sure, I have seen some sprouting weedy grasses in the area I smothered a month ago. A few weed seeds here and there on the imported soil over newspaper are very different from the thick wall to wall green that grew up last year when I didn't smother. It's thousands of seeds to one. Everything was 6' tall and gone to seed when I got back to the house after remodeling so the seed bank is rich with weeds. Smothering is the only thing that'll tip the balance in my favor.

I'm seeding oodles of things I want. CA poppy seeds are essentially free and they are going to be the main element of the meadow I think, since the native grasses grow so slowly. But all these grass and wildflower seeds outnumber those weed seeds brought in by the seed fairies. :)

CJ

But all these grass and wildflower seeds outnumber those weed seeds brought in by the seed fairies. :)

^^^^^^^^^^^^^^^
wrong

I'm not wrong. I'm describing my experience, admittedly done on a small scale.

I was clearing an entire area, smothering all seeds and small plants (grasses, etc). This immediately reduced competition. Then I seeded with a very reasonble amount of seed. Sure I'm seeing some weeds appearing that floated in, but 90% of the seedling plants are the ones I seeded. That seems pretty good compared to what the area looked like before, covered in annual bluegrass, european foxtail and all sorts of other weeds. All of which had left millions of seeds in the seedback now smothered with newspaper.

If I had not planned to seed, sure, it would just get covered in weeds. But by seeding a lot of wildflowers and a good number of native grasses, the wildflowers grow pretty fast and help keep down weeds, letting the native grasses take their sweet time. The germination rate has been very good, but the longer lived bunch grasses take a while to get established, which is an argument for using nurse grasses or just any fast growing *native* grass (grama, big bluestem, etc depending on overall prairie height wanted) in higher amounts versus the longer lived grasses.

CJ

I agree with everything that John Blakeman said except
"that there really isn't such a thing as a wildflower meadow -- at least one that can be artificially created. "
JOhn, it looks like you have a meadow yourself!!! but indeed there is no such thing as an insta-meadow... and yes cardboard works, also you can scrub yourself with pumice instead of takeng a bath and so save water... but i would not recomend that either :-)
and DAmn, jRoundup is hard to get away from ... at least it doesn't translocate and is probably not harmful in soil...but if you want other meathods, look at how a farmer would go about establishing a field of wheat in say 1920.
anyway, i do think that you can, like John evidently has, create an artificial meadow, but you cannot create an insta meadow that looks great all year and maintains it's ecology steadily with no effort... that would be like having children who are genetically engineered to take care of themselves and be nice all the time...interesting in theory.
anyway, it is a myth, a hype by seed companies... at best you wil see anice flush of the anual seeds the first year and the next year it is a lot of weds and the next it is nealy all weeds... but good design and hard work mediated by a chunk of money and/or unlimited labor does work
- A