I don't understand the question, what is it you want classify?

I agree with you inkognito, the header for the thread is somewhat misleading.
The question I am actually asking is in the post. What can I grow on that site?

I am guessing you mean "Do you classify this site as part sun, sun or shade, given the fact that it has both 3-4 hours of hot sun a day, but the rest of the day is in shade?"

Hydrangeas may survive, but they will wilt in the hottest part of the day and will require pretty regular watering in my experience. A medium height japanese maple could provide the shade that the other shade loving plants require - just don't buy a tiny one that will take 20 years to grow in. The hakonchloa and hellebores will probably hate the midday sun as much as the other plants you already tried (although I am surprised about the ladys mantle - that is usually a go to plant in my experience).

I seems like you are looking for a low growing layer of this garden, and so I will assume you are thinking about low growing conifers like blue star juniper or blue rug juniper. Those would probably do well, as they can survive in pretty extreme conditions.

So that brings me around to how I would classify your garden. I would classify it as extreme. Look for plants that can survive extreme conditions. In my zone those would be juniper, daylily, hosta, salvia, actually peonies, lirope, most grasses...

But I am in a very different zone, so perhaps someone here who is in your zone or someone you know in your area who is a gardener could comment on my suggestions.

One last thing, bulbs. Lots of really really cool bulbs- tulips, allium, hyacinth, daffodil, crocus, aenome, frittarilla.

Some more plants for tough situations: heuchera, tiarella, bergenia, ajuga, eupatorium, cotoneaster, mahonia, microbiota.. primroses if it's not too dry, stachys macrantha, (these would grow in my alkaline/neutral soil, but since yours seems to be acidic, try arctostaphylos, blueberries, heather and other acid-lovers).

I have a north facing bed, the best plants in it are an unnamed Japanese maple, peonies, coreopsis, Karl Forester grass, another grass that looks like green meadow grass, but turns a wonderful orange color in fall, baptisia, scutelleria incana? (it's sky blue and blooms early). Also lavender works very well. I've just started growing roses, there are some roses that will take light shade, or part day sun; Hybrid Musks, and a few other classes.

Ask your question again over with both rose forums; there are two-one is Antique Roses, and "Roses" covers modern roses. I'd ask "What will grow with sun from x to x" (give the time of day you do get sun in that spot.) Give your growing zone and if it's hot or cool in the summer...any info you can give them to steer them in the right direction. Hartwood Roses in Virginia is a newer nursery and Connie is very helpful-sned her an email.
http://www.hartwoodroses.com/

It's hot/dry/humid/cold here. Mid-summer it's very dry, and I water at least 1-2x per week. Spring is USUALLY humid and rainy, fall is best, and that's when I'd plant anything.

It seems most plants are quite flexible on the amount of sun if you are in a hot climate, they seem to need the shade to help keep them cool. Some of the plants listed here really like that forest floor type environment, can you give them that, or is that stretching it? I lost three small native magnolias this past year because of all the heat we had, 110F has been ok, but the 115F was just a bit too much.

I have hot dry clay, with lots of sandstone any water gets sucked up as soon as I put it on, even with amendments, it's still a rough go because it gets 110F for most of the summer, and it's a constant battle to keep good soil going.

They do say that fruit trees are best planted on the north side in a warmer climate so they can have more chill hours.

There probably are plants that will do well or at least OK in the conditions you describe (I'd bet on hellebores, and ferns in the Dryopteris family, and actually many others that I grow in those conditions), but another option is to consider whether you really need to put plants there.

Not all foundations need foundation planting. And at the house wall, under eaves, and with light from only one side, foundation is the worst place on most properties for plants to grow.

If you consider your property as a whole, rather than just setting foundation planting as your objective, you might find that you can put the bed further out from the house where more of the sun-loving plants can thrive a bit, you will get an overall better effect than with a few sickly perennials at the house wall. Put just grass or patio at the wall itself.

I have a north-facing front as well were the yard as a whole gets sun only in summer itself - it is a waste of time to put many things that bloom in early spring or fall, as they like to have sun at that time and just don't bloom if they don't get it. So the family of plants that are for part sun/part shade and bloom in summer are your best bet.

Failing this, you need to learn why plants are sensitive to the sun. For example, Brunnera has a large fairly thin leaf, and has no defense against the sun. Hellebores, in contrast, or the sun-loving hostas, can handle it. Other than those, plants with smaller leaves may be better than larger leaved ones. Perennial geraniums might work. And remember too that even plants that can eventually take it may need protection their first year.

Karin L

I second Karen's suggestion that you consider what might happen if plantings are pulled further away from the house.
You could really have fun with this process ...
Imagine that you might plant anywhere or not plant at all.
You might even give yourself permission to consider some hardscape ideas as well. Sidewalks? Stepping stone pathway? Other structural elements? Where might they be and how do they influence where plants should be?
Maybe start looking through architecture and garden magazines, or go to Barnes and pull books, or the library.
At first just look for pictures you love ... Even the ones that you know couldn't happen in your situation. Look at these for a better sense of what pleases you. . The point at first is simply to break out of what your mind's eye currently thinks ... so don't limit your thoughts yet.
Start playing with pictures. With the magazines you could even cut out the ones that really appeal.
If you do come across something that trips your trigger and also addresses the shade - sun issues, note what makes it work.
Hopefully, you will come across some photos that show how plantings away from a house could still create the perspective you want.

Or, maybe the process will surface for you a clearer idea of what you really want here?

If it does turn out that you really find planting up this area to be the right answer for you, then there are two more things that might help:

First, you may have more light than you think. My home is a very soft white-yellow. It reflects a lot of light -- referred to as ambient light in some garden references. I have a beautiful clematis in my north bed that loves this situation . Siberian iris (not tall bearded), weigela (shrub), hardy geranium, liriope, ajuga, and mint are also very happy. (Note: I don't plant mint in the ground because of its invasive tendencies, and like the fact that it blooms way less when grown in mostly shade.)
I'm not in as warm a zone as you, and my north bed is on the back of the house.

I also grow sun-loving hostas, heuchera, hellebore, and some others already mentioned. The other key I wanted to mention is water, water, water and mulch, mulch, mulch. Well amended soil also helps.

In other words, if you are going to challenge a plant you've got to plan to give it the best shot possible. You may have done so already ... but just thought it ought to be covered as a suggestion.

Hope this helps.