I find it easier to make suggestions if there's a photo. Would you be able to post a photo of what it currently looks like?

Creeping sedum would work well.

My first thought was creeping sedum as well. I'm not sure you have enough sun for it though. In my yard, I have it in terrible, rocky, sandy soil in hot, all-day, roadside (i.e. hot sun on ashphalt all day) sun, and it is thriving.

I am trying it in a friend's garden on a small slope of a garden bed, which has very dry soil. The sedum is in bright shade most of the day, and then gets hit with blazing hot sun in the late afternoon/early evening. It is only the second year of this experiment, but so far so good, so maybe it can take some shade after all.

Dee

brigite22 No photo possible? Are the large rocks attractively arranged? If not, hiring some one with a large crowbar or a Bobcat to shift some of them might help.

Here are a couple of photos showing a sloped part of Thyme2dig's (one of this forum's members) garden. The large boulders were a byproduct of construction and/or road building and are placed in an attractive and functional way to help hold the slope as well as looking tidy and natural. She has a few plants in front of the rocks and some spill over from above to soften the rocks and make them look a part of the garden. These beds get a good amount of sun, so the specific plants might not work, but it gives you a good idea of how beautiful a hill (or mound) can be.

This one has rock steps going up to the top, while the front has brick and wood steps. You might want to consider adding a path or steps up onto your mound with a path or stepping stones on top to help it look like a deliberate garden rather than leftover rock and soil.

I like the way T2D uses a mix of shrubs and perennials, densely planted and mulched to help reduce weeds, to keep the area beautiful year-round.

With a bit of planning and some care, this area can most likely look like a planned garden, not a leftover heap. I would start with planning whatever hardscape you want to add like steps, paths, garden art, etc. If you add paths, I'd put in edging to keep the groundcovers out of the pathways, but with stepping stones, just be sure to plant low growing plants in the walking areas. Leave the accumulated leaves there (though you can move them off your rocks), but pull any weeds and do any hardscaping. Over the leaves, put down a layer of corrugated cardboard or a thick layer of newspaper (wet it as you go to keep it in place) and then a good layer of hardwood mulch, again leaving the rocks exposed. This type of mulching is key to making the area low maintenance as it will keep down weeds and hold in moisture in a way that groundcovers alone won't. You will probably need to spend a couple of hours late spring and fall weeding, but not more than that. 15 minutes a day for two weeks a year is doable for most folks. Every few years you will need to add mulch until the ground cover has completely filled in.

Consider adding plants with a variety of heights, leaf size, color and texture.

Low maintenance, lower shrubs that are fine in somewhat dry afternoon shade:

Microbiota decussata (AKA Russian arborvitae) evergreen

Any of the smaller Hydrangea paniculata varieties such as 'Little Quickfire', 'Little Lime', etc. (none of the other Hydrangeas are tolerant of dryness, but H. paniculatas are.)

Low bush blueberry (Vaccinium angustifolium)

smaller rhododendrons such as the various R. yakushimanum such as 'Ken Janik', 'Yaku Prince', 'Yaku Princess', etc but you may need to water if it is really dry for really long

Diervilla (bush honeysuckle)

Perennials that would work with your light:

Anemone sylvestris - spreads

Partridge berry- (Mitchella repens) very low

some of the smaller gold-leafed hostas which tend to be more sun tolerant

Heuchera (coral bells) and Tiarella (foamy bells) and Heucherella (a cross between the two previous)

Japanese forest grass (Hakonechloa macra) ‘Aureola’ gold foliage

Carex 'Ice Dance' or C. 'Banana Boat' (along with many other Carex which often like part sun and tolerate dryness) - spreads

Lamium maculatum (deadnettle) - spreads

Ground cover Epimediums- spreads

smaller daylilies like 'Happy Returns'

Hellbores will spread via seed, but not aggressively

Smilacina racemosa (false Solomon's seal) may be listed as Maianthemum racemosum - will spread via seed, but not aggressively

Assarum spp (wild ginger, but not the edible kind) slowly spreading

Polygonatum spp. (Solomon's seal) will slowly expand clumps

Iris cristata (crested iris) will slowly expand clumps and is only about 6" high with light blue or white spring flowers.

Some of the hardier Alstroemeria such as 'Sweet Laura'

Geranium Bevan's Variety or G. macrorrhizum or G. biokovo

Campanula poscharskyana

Pulmonaria (lungwort) will spread via seed, but not aggressively

Phlox divericata - (woodland phlox)

Dicentra eximia - (fern-leaf bleeding heart)

Pachysandra (kind of boring, but would be OK as part of a mix) - spreads

You might want to put in some smaller daffodils and species tulips in the sunniest spots for early flowers.

Have you considered a mixture of various drought-tolerant plants such as sedum, sempervivum (hens and chicks), ice plants (delosperma in various colors), cacti (prickly pear opuntia thrives). yucca (many types). coreopsis (such as moonbeam) and also lavender, just to name a few. None of these get too high so your boulders would remain visible. The flowers of the cacti, ice plants, coreopsis and lavender are very attractive too, and the foliage and textures are good combinations and contrasts. Spiky yucca among fine leaf coreopsis, cactus pads amidst blue-gray lavender foliage, etc.