I had a client that had a whole bed of stachys - I too am in the Midwest and find that it has cycles where it becomes invasive and then rots out leaving big bare spots for weeds to gain a foothold. It's a nice plant but short-lived and I use it sparingly and only as an accent. So I would try interplanting with Prairie Dropseed and/or Wild Petunia (Ruellia), some nice native sun tolerant sedges and Prairie Sundrops. These guys are rugged enough to compete against it if you clear out a section for them to be interplanted.

Ladybells - a terrible plant. Roundup and smothering are only minimally effective since this plant has deceptively huge roots like carrots which carry huge reserves. You will have to bite the bullet and spend the time physically digging these up - this is the most effective method. Do not plant anything in this area in the meantime because ladybells usually require a second or third thorough digging to get permanently get rid of. I would not under any circumstance replant this anyplace else.

Buttercup - there are better plants then this. Dig up and do not replant. I find this plant does not like neighbors and really smothers other coexisting plants - even larger plants like Monarda have a hard time competing because the buttercup forms such a thick mat, reducing the amount of water and nutrients.

As for the Ajuga - I agree it's invasive but at least it's easy to dig out, it's very shallow rooted. Maybe place it in an area where it's dryer with less water and it will be less aggressive.

I know there's alot of talk of replacing lawn with groundcovers because of water concerns but in most cases it's just replacing one monoculture with another (usually non-native) which isn't terribly healthy either. Think about all the problems farmers have with these vast fields of corn and soybeans and you'll see what I mean.

Diversity of groundcovers using various small to medium sized perennials (using native or non-invasive non-natives)is the key.

Good advice, thanks.

I think my stachys has that virus that turns the leaves yellowish. Would that hurt the new plants? I don't mind it out by my mailbox, and I'm relieved to hear that it's not as dangerous as other plants.

I wonder if I could cover the entire area of ladybells with several layers of cardboard, newspaper, and yard waste? Just basically start a deep lasagna garden over the top of it, and fill with Echinacea, Rudbeckia, and other tough plants? I don't mind digging, but I could start the lasagna now- which would be a plus.

I call my buttercup green cement. I am tempted to plant it in my dirt driveway. I nearly killed a pine tree this year with it. What was I thinking????

Good idea for the ajuga. I know just the place for that.

Also great point about the groundcovers.

What's your feeling about thyme and chamomile mixed with dutch white clover, mint, and whatever fescue survives?

How big is the area that you're trying to redo approximately? Do you have a picture?

Regarding the thyme - I like this plant, if it has good drainage it will spread fairly quickly. The only snag is that because it forms a loose mat it's really tricky and very time consuming to dig out other weeds (i.e lawn grass, clover etc) that may interseed because often times you end inadvertently ripping up most of the thyme.

For this reason, I use it in small areas where I have the time to take out any weeds and other plants which may encroach. Plus, it's a nice plant that is best appreciated close up such as between some stepping stones or near a doorway.

Clover - I've seen posts for and against this plant. Yes, it's a good plant for fixing nitrogen and thus improving the fertility of the soil. But, it can be a real thug and hard to control if it gets in with other perennials or other groundcovers. I've had situations where it's encroached on other plants and I've had to dig up entire sections of perennials and pick the clover out of the roots of the desireable plants.

Mint - Same applies to mint. Best use for it is in decorative pots where you can enjoy it for cooking purposes rather then as a groundcover.

Ladybells - The idea of cardboard and yard waste on top - it will work only if you can exhaust the roots. If you dig one up you will see that they are huge. I would try it especially if it's a large area. But I would not plant any other perennials for at least a season. Just heavily mulch on top of the cardboard and yard waste and keep clear of other weeds. But if it's a small area it really pays to dig it up.

I don't have a good picture of the whole thing right now, but I'll see if I can put some pieces together to show you. The yard part is at least five acres- some of it seasonally flooded. I have different large beds and gardens throughout.

I want to get rid of all the turfgrass, and have a mixed groundcover lawn. I like biodversity. And bugs! No need for a manicured lawn- or any lawn for that matter. Just basically mowable.

Thanks for all the good advice!

If I was doing your project I'd try to select an area and completely clear it of all vegetation, then plant. i'd pick fairly large areas but not the whole yard at once, and plan to take at least a year before deciding that the weeds are gone. I might turn over the soil with a shovel, removing any weeds i can and repeating numerous times. i might smother some areas with thick mulch, perhaps including cardboard or newspaper underneath. i might even try roundup, again with repetition. In any case, you don't want to plant anything new in an area that is infested with a weed, or the weed will return and you'll have to pick them out one by one forever.

I agree with the above. Clear one area, then keep hitting it with roundup until nothing comes back. Do this over a long time. Repeat tilling would have a similar effect, but also dig up weed seeds. Even Kudzu eventually dies with this type of persistence.

Rototilling can also cause more weed seed to be exposed and sprout. It's a mixed blessing. ;-)