Would this work?
I have a stretch of irregular ground with kind of lumpy lawn at the bottom of the yard. Last year I decided to just turn it over to the wildlife and left it unmowed except for a mowed pathway. It looked like, well, unmowed grass—not particularly attractive. I thought this year I might try digging a few holes in the unmowed part, filling them with potting mix, and dropping in flower seeds to get a wildflower meadow effect. Or maybe it would just look a mess, I’m not sure.
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Or at least I think it will. 
Wildflowers can spread
I'd get a dark waterproof tarp or dark plastic garbage bags and put them over the section you want to change from grass. In about four weeks, all the grass and weeds will be dead without light or water. Then, you can do anything you want.
Again, to minimize maintenance, perennials come up every year. Locally, folks sell from from cuttings or plants they've grown in their own backyard. So they're cheap and you're helping out the little guy (often an elderly lady).
If you don't care for weeds, weed screen with mulch if you can handle that kind of manicured look. Aside from water and fertilizer, there's no maintenance. Some cities will provide compost (as fertilizer) for free from their recycling. You can add rocks or a bush to make it a little more 'natural' with some heights.
We have had some success putting wildflowers in a half barrel or big pot and they haven't spread too much.
You get the ground bare and free of weeds - you can do nearly anything. 
We got rid of our grass in the front and back of our house entirely.
