I have a similar issue. This is what has worked for me thus far:

Hosta

Phlox subulata

Mazus reptans

Cranesbill

Lady's Mantle

Japanese Forest grass

Sea Oats grass

Daylilies

Lavender (English)

Liriope

Astilbe

Epimedium

I always find it easier to make suggestions with a photo since it answers many questions for me, so if you can add a photo that would be nice. How large is the space? Does it edge a wild area or another yard or is it an enclosed bed, sandwiched between house and drive or other paved area? Can you water and mulch? How steep? Are the rocks what make the soil poor or is it sandy or subsoil from construction or sticky clay? Are there tree roots growing in from the edges, and if so what kind? What currently is growing there and have you tried planting anything so far? Can you add contour, a rock wall, or boulders? Do you have any particular kind of plants in mind or a general height - trees or shrubs or perennials or groundcover?

I'll make suggestions when I have a better feel for the space and what you are looking for.

Gernanium macculatum? Cinnamon ferns? Arrowood Viburnum (Viburnum dentatum)?

I have attached a photo of the problem area that we would like to improve with plantings. It's the banking (small hill with approximately a 75 degree slope) behind the seating area. Basically running from the edge of the cottage to the to the right side of the photo.

Thanks

It looks fairly shady - are those red maples?

Hosta

Astilebe at the bottom where it may be more damp

lady's mantle (Alchemilla mollis)

All of Gardenweed's suggestions

Mountain Laurel (Kalmia latifolia)

Iris cristata (crested iris)

Iris siberica (Siberian iris)

Tiarella (foamy bells)

Polygonatum (Solomon's seal)

I'd suggest a visit to Garden in the Woods (New England Wildflower Society) in Framingham to get some ideas and as a source of native plants that may do well there.

The trees are oaks and some type of pine,

I took the picture around 7pm last Friday night; could be the reason it looks so shady.

Thanks for the plant suggestions and Garden in the Woods recommendation.

Oaks are easier to plant around since they have deeper roots than maples, so not as much competition for water. More probably a fir, spruce, or perhaps hemlock rather than pine per se. (Pines have needles in bundles, and the look isn't right for that.)

Suzanna and Ed have good suggestions also, but I wouldn't use Virburnum dentatum as it's quite susceptible to viburnum leaf beetles IME. I also found it to be highly overrated as an ornamental plant. Look at other Viburnums such as 'Mariesii' or cassinoides or 'Shasta'.

Is this at your place in Maine or in MA? If it's in ME, I'd think about when you will be there and choose plants that will be at their best when you are likely to be in residence. So for instance, Hellebores bloom about as soon as the snow melts and will be done by May, and Trycirtis blooms in the fall, and if you are only there in summer, they probably aren't worth planting.

It's the place in Maine.

The community is open from May 1st until October 31st.

Mostly there from mid-June to mid September...

Thanks for your help...Any suggestions you have are appreciated.