Help with Plan: Massively Overgrown Yard
My backyard has been severely neglected for years and I have recently begun the process of reclaiming it. I'm looking for a little help/advice on the best way to go about this, taking into account what I'd eventually like to do with the space. It's approximately 65' x 65', north facing and very sloped, rising about 12' from the base (at the back of my house) to the edge of the property line 65' behind me. There's one flat area (full sun) at the bottom, and a second mostly flat area about halfway up (light shade). I'm working in zone 8b (North Florida).
The entire yard has been overgrown with thousands of small shrubs and trees (up to 12'), miles of thorned vines, weeds and very sparse grass (unknown type), clover and ferns beneath. I recently spent two weeks with the chainsaw and clippers meticulously removing each and every tree/shrub so that now I can actually walk the property, the only problem being literally thousands of 1/2" to 2" stumps everywhere, plus the miles of tangling ground vines. I started with a mattock yesterday and cleared an entire area of stumps, just over 100 in a couple of hours, and have no problem continuing this until all of them have been cleared. But what I need to figure out now is what to do to prep the soil for whatever comes next. I can't begin to imagine trying to weed this whole space by hand.
My yard appears to be entirely composed of clay (my neighbors tell me tillers don't work here) and after clearing an area of trees and stumps, it's left almost entirely barren save the endless systems of subterranean roots (some 2-3" thick!). At this point I don't know if I'll want to plant grass here later or some other ground cover like clover or ivy. Because of the extreme slope of the yard it's not very conducive to play activities so grass seems to make less sense. What I'm most concerned with is killing the tens of thousands of small weeds and vines and preventing them from coming back. Doing some research into this is when I discovered the idea of sheet mulching.
Sounds good, except that I'm still working with a total area over 3600 sq. ft, on a strong slope. I can get my hands on enough cardboard to cover the area, but trying to mulch 3" on top of that doesn't seem to be within the realm of human possibility. Bulldozing is not an option due to the spacing between houses.
I've attached a picture of what I'd like to eventually do with the space (rough draft), with the idea that I could install the raised vegetable beds as phase one (next 4 weeks), then get at least a handful of citrus trees planted in additional raised beds built into the lower sloping section of the yard this year. Ideally, I would get all of the trees planted this spring to get them growing, and then work on the space around them over the coming year to prepare it for ground cover.
So...what are my best options? Can I cardboard mulch, minus the actual mulch, just to kill some of the crap on the ground? Is sheet mulching even appropriate for large areas on which you intend to install ground cover rather than garden space? What else can I do?
Forgot to mention that I have a large, centrally placed Southern Magnolia on the upper flat terrace, plus a large oak (70') and multiple smaller oaks lining the rear property line, all of which shade the back (upper) portion of the yard.