The nature of capitalism is for purveyors of glyphosate to give you the minimal formulation required to keep most customers happy. Many who whom are just killing relative pushovers like annual grasses. I'm convinced a lot of formulas (including some "contractor" grade ones) are not quite as strong as they say they are. I don't even mess with consumer grade material but I assume you don't have acres of this stuff. So just buy whatever they have at HD or Lowes. Use the maximum dilution - or a little bit more, maybe 30% more, but double the maximum dosage will just be wasteful or counterproductive. For a 40% glyphosate the max dilution is usually specified as ~6 oz per gallon. Add just a little bit of soluble plant food like miracle gro - 1/5 of the recommended dose so a bit less than 1/4 tsp. The plant food will encourage the vinca to take up the glyphosate. Add about a 1/2 teaspoon of dish soap per gallon. Consumer formulations claim they come with a surfactant, but in my experience for some weeds it's not worth a darn. Obviously, spray on a day with no rain 8 hours before or after. IMHO, the best time is late afternoon. Trust me, the Vinca (and any young PI) will start dying in a week and will *not* come back if you do it right.

Your vine with the orange roots sounds like Celastrus orbiculatus, Oriental Bittersweet. VERY invasive and destructive exotic vine, it has laid waste to some beautiful large native trees in this area. And yes the roots spread far and wide sometimes. Cardboard will work for the immediate area, but if you really want to whack these guys, you need to either persistently pull or mow them, or use an herbicide. A small amount of Glyphosate or Triclopyr concentrate can be applied to the cut stems and will be absorbed by the roots and kill them. Or after they leaf out you can spray Roundup, carefully because you don't want to spray adjacent vegetation (active ingredient in Roundup is Glyphosate). I usually do just pull the smaller vines, was just doing that yesterday as a matter of fact! Ugh.

I second the suggestion for the dwarf nandinas - we have them in our south-facing front flower bed completely under the eave of the house, so they get next to no direct sunlight (and barely any water now that they are established) and are thriving. They're evergreen in our area and stay small (and are almost always available at Lowe's in the smaller sizes which are less expensive than the big ones. If you can stalk Lowe's and HD, they will clearance a lot of those types of things at the end of the season before they bring in the Christmas trees, so you can get a deal but I doubt you want to wait that long with the cat issues ... the skewers in your photo made me laugh - I can tell the situation is getting desperate!). You can see two dwarf nandinas directly in front of our windows in this picture - they're in the shade so look dark but in person they are kind of lime green and bright. I think nandinas alone might be kind of boring, but it depends on how "into" gardening you want to get as to how elaborate you might want to be. This first year as you wait for your shrubs to grow, you might want to plant some inexpensive annuals to fill in (coleus is a good one for shade and is pretty easy to grow from seed, although I've always done my seeds indoors in the early spring.) Golden moneywort is one of my favorite creeping perennial groundcovers, you don't need too many plants to get started and it will fill in and keep weeds down for you and it can get a little ratty in the winter but does stick around to some extent, so it's semi-evergreen. I'd add some seasonal foliage or flower interest with heucheras or variegated hostas. All those are in this picture with the hydrangea (which is definitely a thirsty beast!) I'd definitely add bulbs like daffodils that will bloom when there are no leaves on the tree. Lots of things can be divided from other gardens - do you know any gardeners in your neighborhood or do you walk your 'hood where you could maybe ask a gardening neighbor? If you end up wanting to go the liriope route (I do actually like monkey grass in a landscape, at my old house it edged all my beds, but it needs to be divided every few years to keep from taking over and it is physically hard to divide) for goodness' sakes don't buy any. Send me a message and you can bring your shovel to my house. I also would be able to share daffodils next spring - I'm not entirely sure where they all are this time of year. My hostas are still small and young (divisions from friends, all!) so I can't divide those yet, but I might have some other things to share if I walk around and look. Oh! And get some cat repellent. We had that problem when we moved into our new house about 12 years ago, with cats using our raised planter beds as a toilet, and I went to TLC for cat repellent - probably any nursery will have something like it. The kind I used smelled strongly like lemons and was a granule that came in a milk carton style container. You'd just shake it out over the soil and reapply every time it rained, and after a while the cats got the message. I dug out all the top 8 inches of contaminated soil and replaced it, but I am a germaphobe who tends to garden while gloveless. Then I planted new stuff and it filled in and the cats didn't come back.

The bloger mentions a problem with her Pink trumpet vine self layering. I never had that problem since my plant stayed upright by leaning on and through the lattice. It is a huge plant that's for sure. The root ball got bigger, but it never spread by runners in my yard. It was about as trouble free a plant as there could be for me. No leaf diseases, no bugs ate it and the blooming period was a couple of months starting early September. I wouldn't mind having a couple of her layered plants! :-)