You know, that's a really compact clump of yucca- instead of fighting it, why not use it along with the cedar and other shrub as winter backbone? They do have nice fragrant white blooms in summer. If it were spread out or a huge clump, i'd fuss with it, but if you're wanting to make life simple... leave it be. I'd say it depends on the compost whether you till it in. If it seems like it has a good bit of earthy stuff for the plants to dig into, then no, but if it's more top dressing stuff, perhaps till in half and top with compost. The quality can vary year to year and by the time of year, depending on what they are shredding and composting. If you're in wake co, you will need to find a truck/hauler to haul it for you, but the compost itself is fairly cheap- like 30 a big truckload full. City runs 2 for 1 specials sometimes, too. Meaning pay for 1 load, get the second free that same day- but you'd still need to pay for hauling. You could do a lasagna type bed- layer on newspaper, ect, and build up with out messing with tilling at all. There's been a good bit posted about it, and there are at least 2 books. It really does work if you have a little patience/time. There is a thread for the swap on the exchanges forum. It should have the where what when info- tho i can tell you quickly it's may 8th, at white deer park in garner. Doesn't matter if you're a newb. We always have some. Just bring some good food and anything you have to spare that you think gardeners could use- pots, hoses, rocks, etc. Even shallow boxes would be appreciated as folks always need them to haul away their new found goodies.

native that is 4 ft tall for me in my n side garden is thalictrum. I have to grow it in an attractive wire pointy thing ( can't think of the name) to protect it from the wind. Mine grows- about 18 inches from the house- so full shade- but I have it easwhere in full sun. It is sprouting already. If you want to buy some emial. NW corner of IL.

My butterfly weed (asclepias) did pretty good in a compact clay spot I hadn't amended. So did my pincushion flower (scabiosa), though I've never seen that attract that many butterflies. Most everything else I've ever had does so much better with amendments. If you mulch it every year, and turn the mulch under as deep as is easy with a shovel in the spots where you don't have plants in the fall, it will take 3 years to notice a difference but it will help your soil a lot without too much effort. (I say in fall because then you won't disturb your perennials because you'll still know where they are.) So if you plan to stay where you are that long it will be worth it eventually.

You can certainly walk on a Cotoneaster groundcover. It will tolerate foot traffic easily, which is why it is often used as a groundcover in commercial parking lot applications (parking islands). It just doesn't have the same even surface something like a lawn or a mat-like groundcover would produce so not as comfortable to walk on but still immensely tolerant of foot traffic. FWIW, there are scores of woody-based or flattened shrub-like groundcovers available - cotoneaster, kinnikinnick, ceanothus, Rubus calycinoides, salal, wintergreen, junipers and various vaccinium to name a few. While not offering a smooth, flat surface like a lawn, they are all walkable and handle foot traffic easily.