I have seen and planted such gardens and they don't bother me a bit. It's a matter of taste but I think it would look just fine. Call it a "naturalistic garden" like many others do already and then it will suddenly look more appealing to you. I also allow volunteer plants in my gardens if they are not invasive or horribly incovient (what's wrong with getting a plant for free?). A lot of garden design has been getting away from neat rows and formality anyway. Mark where your surviving perennials are so you know not to dig in those spots. You can also transplant in some already grown plants to add to those you already have and thus make designs, etc. that are more pleasing to you. A little mulch around your plants will make them look like they are there on purpose. Also, if some of your plants just can't stay exactly where they are then try transplanting them to a more convenient spot when it's not so hot out rather than killing them outright. I wish you the best.

Thank you bob64 for everything you said.

I'm just a beginner in hillside gardening, but I'm wondering if it would be possible for you to build a retaining wall and fill in with better-quality soil behind it. Or dig terraces into your native clay and then put the better soil in the flat parts?

We have a planned mix of perennials, shrubs, and deep-rooted ornamental grasses on our hill, and as things are slowly maturing it looks great. We are using mostly drought-tolerant natives. We have clumps of Little Bluestem, Switchgrass, Rudbeckia fulgida, Echniacea pupurea, some phlox subulata for early spring color, serviceberry, one eastern redbud, and a couple grey owl juniper. There are a few other perennials I am thinking of adding for early summer color.

Basically, my rule is that if it needs anything more than once-a-year cutting back and the occasional hose in the middle of a dry spell, then it does not go there. Anything that isn't hardy enough to make it on its own will just not make it.

May I make once suggestion? Seeding a hill is difficult, blankets or not. If you want more hardy perennials mixed in, seed them up in pots and then transplant them when they have established enough root to hold them onto the hill.

Right now my coneflower and black-eyed susans are in full bloom and they look fabulous. Our local garden center has a hill that's about 85% shrubs and small trees with some perennials and grasses mixed in, and it looks great. Leave the perennials you have and go ahead and plant the shrubs around them.

All sounds good! Thanks. However, I am trying not to build retaining walls or something constructive due to budget. Very good idea though. I probably would have built a retaining wall if my budget was allowed:-)

I hear ya chueh. Terraces and retaining walls are usually a good idea but they are often expensive if done correctly (unless you have sufficient skills, help and equipment of your own). To slow the flow of the water you can stake in wattles into shallow trenches. You can can probably buy the wattles from whomever sold you the erosion control blankets. I like soitgoes' plant list.