This is the area of overrun

To get rid of your "weeds" the area will need to be sprayed thoroughly with an herbicide early in the season when they start growing, again when there is regrowth, and then later in the season to kill off anything that persists. The reason I put the word weeds in quotation marks is because I can't believe everything growing there would be truly classified as a weed - take a closer look, there are probably some native plants that would be more suited growing at this site than anything planted there. The weed removal is a process, not a one shot deal. It will take at least one full season to fully get rid of what is growing there now. Be aware of what is called the seed bank - that is the dormant seeds that remain in the soil of everything that has grown there previously - weeds - and they will return every time the soil is disturbed (cultivation) and every time you clear the ground removing the weeds by pulling them up or by using an herbicide. Nature does not like bare soil and will cover it over with something, whether it is the leaves from trees that fall in the autumn or herbaceous plant growth. Once you have gotten rid of your weeds I would recommend putting all of your fallen leaves and grass clippings over this area to mulch it with organic materials using what you have on hand. If you don't like the look of leaves, just run them over with a lawnmower to shred them. This will greatly improve the quality of the soil in the bed, and keep the weed growth down. Do it every time you cut the grass and every autumn when your leaves fall from your trees.

Once you have cleared the bed of weeds and have mulched the area it can be planted with the desired varieties of plants. You will have to maintain this spot, keeping it mulched and weeded yearly or it will quickly return to its original state. Again this is not a one shot deal, it will take time and patience. Good luck and have fun with the project!

P.S. If I had an area like this in my yard I would just plant more grass to make my life easier!

In addition to Jeb's good advice, a question -- what sort of plant do you have growing at ground level in that patch? In my yard's wild area I fight "creeping charlie" -- a low growing member of the mint family. Pretty purple flowers in early spring, but it smothers everything other than established large shrubs. If you DON'T have it, you're good. If you DO have it, plant a cover crop such as winter rye that will smother the creeping charlie after a few seasons.

Also consider -- you don't have to do your whole border at one time. You could choose a five or six foot length, get it weed free (by hand, not chemical) and planted with wildflowers, and see how that fares before tackling the whole project. To fight the weed's seed bank, use wildflower plugs and sprinkle with Preen.

A lot of your 'Tall Weeds' are very likely to be late season wild flowers that should be blooming now if they were not mowed down mid season.

Converting the space to wildflowers, adding more blooming weeds, for pollinators will necessitate you learning to identify your 'Tall Weeds' and being able to accept some actual weeds growing with your wild flowers as nature intends. Maintenance is just about the mowing regimen and selective removal of aggressive problematic weeds you have properly identified.

These are 'Tall Weeds' in bloom.

the base question is... how much do you want to garden ... are you willing or interested in spending hours per week out there maintaining flower beds ... if the answer it no ... then just go back to grass ... and be done with it ...

if you are willing to invest the time and money to create proper flower beds.. and mulch and maintain them thru the entire garden year ... on forward in time thru the decades ... .then go for it ...

that your weeds can get so tall .. indicates to me.. that you have a life or responsibilities beyond gardening ... and creating more work for yourself.. may not be the thing to do ...

once you make that decision ... we can help you forward ... but do understand the work and level of commitment you will need ... its not really as simple as picking some plants.. and just planting them in that weed patch ...

ken

You can smother weeds with months of weedblock fabric. Cover it with mulch to make it better looking. Then, plant through the weedblock (after most of the weeds are dead, which could take a season. Plant native Clethra, not butterfly bush.

However, most plantings, even with weedblock, need occasional weeding.

Native wildflowers that tend to be tall at this time of year are goldenrods and various asters.

If you have to weedwack, you aren't mowing, so I'd recommend fairly densely planted low-growing shrubs.

Do not plant through fabric! You'll rue the day.

"keeping surrounding competition suppressed using black plastic."

Don't use plastic.

Water needs to be able to penetrate so all those lovely soil organisms stay healthy.

Like laceyvail says I wouldn't use fabric either- sooner or later it becomes a problem.

I just plant, mulch well, and deal with weeds by hand or using a weed torch.

I find weedblock really effective. It's a hell of a lot better for tge environment than Round-up. I have areas of my garden infested. I pull up the weeds and put down weedblock. In a few years, I can pull it up and most of the roots of nasty stuff are gone. My young plants have grown sturdy roots and can tolerate weeding. I have creeping bellflower, which has deep, forked viscious roots. You just can't pull them all out znd herbicide doesn't work. It just kills the leaves.

I have no interest in using a torch anywhere near the siding of my 100 year-old house, and my plants/weeds are closeish to it.

Landscape fabric is a good tool, Like anything in gardening, it's not a magic solution.

Thank you everyone for your thoughtful suggestions. I don’t think I’m inclined to go with grass (fescue?) bc that location would require trimming around lots of trees, etc. I’m really trying to achieve what the last pictures show, which are coneflowers, black eyes Susan’s, daisies, butterfly bushes, etc. maybe I can take up more space with a few evergreens like moonglow junipers or dwarf Norway throughout. Sounds like we may need to tackle this in sections and see how we do. Again, thank you!

Please don’t use herbicide.

The rudbeckias ('goldsturm' or other rudbeckia fulgida types) are probably your best choice to get started, they're a native wildflower which will fill in well and doesn't mind an occasional mowing or weedwacking when things get out of control.