I'm in zone 5b/6a and we usually get an average of 40" of rain per year.

Our neighbor was putting in a new garage and offered my husband the "good" top soil that they dug up. He was happy to take it. When we got home, we saw that the "good" top soil was junk. It's clay with rocks from pea-sized to 3". With some coal mixed in for good measure. The clay is orange and very dense--I could probably make pots out of it.

So we have a berm at the back of our small property that is 4' high, 8' wide at the base and 25' long. One side faces SE (full sun) and the other NW (almost full shade).

It's been there a couple of years now and we call it The Mound. I tried sifting it but Ugh! Plus, there's glass in it. Getting rid of it would be $$$. So I want to cover it up with perennials.

Any ideas? On the shade side, we've thought about vinca and mahonia repens. On the sun side, we've thought about Russian Sage, coreopsis, some kind of grass (sterile pampas?), mockorange, daylilies. I don't know if any of these would work. Any ideas?

I'm not sure if it is wet or dry since it's clay but it's also sloped a lot. It has rocks for drainage but it's also that horrible clay. It's at the back of the yard by the alley so it would be very difficult to water. We have a small yard so we can't have anything that would be invasive (by seed or runner). Low maintenance and long blooming would be a dream but I know I can't be too picky.

http://www.mgofmc.org/perennia...
See if this list helps.

Thanks for the link. I'm still not sure which ones would work in this soil. I don't know if it would be considered moist, average or dry.

You can keep amending the soil so it improves the condition of it so you don't have to deal with bad soil anymore

Mock orange that I have grows like a weed and it does not care where it is. It is in shade in bad soil, it is in sun in good soil it does not care where it is it grows and blooms.

The other do not care plant is Sedum Autumn Joy. Sedum Brilliant, Sedum Neon.

Hmmm...tall sedum. I've been wanting to try tall sedum anyway. And it might mix nicely in front of some dwarf, upright russian sage. I like that. I can imagine a wave of sedum splashed across The Mound.

Thanks for the tips on the mockorange. I have two but they are planted in my normal (heavily amended) garden beds. I've read that they can tolerate poor soil but I wasn't sure. I also like the idea that they have great autumn color.

I like hardy geraniums , they seem to grow anywhere I plant them . they range from ground-cover 8'' to 24'' almost bushes.

I even have the tall Sedum in some pretty dark shade. Frosty Morn, and because I had so much of Brilliant I have that one in the shade also.

Mayber shape the top of it into a saucer, or dig a few holes that will tend to hold rainwater. Then you'll hav e some spots that will be more moist.

That would also be a great place to sheet-compost or spot-compost coffee grounds, kitchen scraps, grass clippings, yard waste, paper or anything organic. A few bags of dried manure. The saucer will hold anything of value until it can filter through the clay and start the soil-ification process.

Any amending you can do to the top few inches, even if only in one spot or strip, will let some plants get a toehold and break ground for fussier plants next year.

Sloping sides, especially the side that slopes down to the lower side of your pre-existing garde, will be drier.

If your yard slopes down towards the berm, the foot of the berm facing your yard may actually be a wet spot, especially if the berm has a convex curve on that side instead of conave. .If you want to conserve (or divert) rainwater, it might be worthwhile shaping the "wings" of the berm to either retain water or let it run away.

Then you might try low-cost low-effort "natural selection". Plant any old thing wherever the clay looks least bad.

- When you see something that looks hardy being discounted at a big box store, buy one small pot and dig a hole for it.
- Any overage seeds you might have thrown out, scratch the surface with a rake and scatter some there in a rainy season.
- Buy some cheap seed MIXES, or trade for them online, and scatter those on the clay berm.
- Buy a few pounds of a clay-tolerant cover crop (feed store or farm co-op) . Scatter some before every rain.
- If you see something tough-looking thriving by the roadside, or in a neghbors yard, dig some up and plop it in, but only IF you can ID it as not too invasive in your climate..

Whatever survives was the best choice! Anything that can force any roots down into that mess will gradually break it up for you.

An ambitious alternative would be to re-distribute some of that sticky, rocky clay. Use it as a building material or re-grading parts of your yard. . Do you have access to a team of brawny assistants? Or power equipment?

1
Use some of it to build walls for raised beds around your yard. Maybe even build up a 12-18" "platform" of clay under a really high raised bed. As long as there is a drainage channel UNDER the downslope part of the new wall, you can fill the center with better soil and have that bed rasied above grade, for a really deep root zone..

2. More ambitiously, chnage the whole grade of your yard for improved drainage, or more water retention. If you have any low spots, move the good topsil aside and fill that low spot with junk clay, then move the good soil back ... now it will above grade and well-drianing.

Maybe create a south-facing slope tio get more sun for one spot.

Just read a review in Fine Gardening about Cool Splash bush honeysuckle (Diervilla sessilifolia 'LPDC Podaras' which will do well in dry shade and hard clay soil, as well as sunnier more fertile areas. It has pretty leaves with a white margin, and yellow flowers. Attracts butterflies and hummingbirds, deers don't like it. Spreads by underground suckers, so you'd need to watch that. 2-3' tall and wide

Very pretty! Is this it??

Wow. I like that honeysuckle! That as some real possibilities.

Thanks for all of the suggestions. Every idea helps. We don't have any brawny helpers. DH and I are overweight, sorta middle-aged and both have medical issues. We do what we can.

Yes, sure does sound like a good possibility for zone 5.