Lawn --> No-Mow on Slope Questions

Hey Guys!!

I am new to this board and I LOVE all the content. It's amazing and so useful!

I am familiar with permaculture practices and want to start transitioning my home to reflect these ideas.

So I have a sloped front lawn and I want to transition it into a no-mow area that supports pollinators. The current soil is clay and I live in the southeast, Zone 7. The area is about 20 feet x 25 feet. You can see it in the attached picture. I roughly know what native plants I need but what I really need help with is, is how to prepare the soil in the most frugal way possible. I would like feedback and I'd like to know if this can be done without building a retaining wall.


I am thinking I should follow this process:
Layer 1: smother lawn with cardboard
Layer 2: add 3 inches mulch
Layer 3: add soil  


-How many inches of soil is suggested?
-Will everything stay in place on slope or do I have to take measures to protect against erosion? Can plant rooting mitigate the erosion question fast enough? Thinking lots of fast growing groundcover here.
-What are some alternatives? I was toying with the idea of laying down the cardboard or a weed barrier fabric and then stacking down burlap sacks of mulch and dirt overtop, and fixing them to the ground with stakes.

Geoff Lawton has a short video about sheet mulching (probably a lot more than one, but I remember this one):


Seems like you'd put down the soil and any organic material you have, then overlapping cardboard that's been soaked in water, followed by the mulch. I could see a heavy downpour washing the material off the cardboard, so if you can put a little edging of any sort on the bottom of the slope, and add additional material on the lower side to level it a little, that should help.

One idea might be to establish a wildflower meadow. I have done that a few times and loved the results. My current meadow is now 7 years old and still going strong, with only a single trim a year.

If you like that kinda thing, this thread has lots good stuff on solarization, which preps a lawn for meadow planting in a few weeks: https://permies.com/t/43714/info-Soil-solarization

Great ideas!