There are tons of plants that will grow in shade. I don't where you are, but the northeast wildflowers, ferns, ferns and more ferns, Leucothea, Pieris floribunda, among others.

Here is a link to the FAQ on this subject.

Here is a link that might be useful: FAQ: What will grow in dry shade?

It would help to know what part of the country you live in.

Shade and acid soil are a blessing in my woodland garden. I wish I had a picture handy of my shady retreat, located under a massive white pines surrounded by dogwoods and eastern redbuds. It was "a void" when I moved here 5 yrs ago but it's now the most beautiful part of the entire yard and a favorite spot to hang out on a hot day.

I have a number of perennials and some shrubs growing there. Among them is; heuchera, (coral bells) hardy cyclamen, pulmonaria's, Virginia blue bells, Carolina beauties, hosta's, bleeding hearts, jacob's ladder, European and Canadian gingers, trilliums, clethra, lots of ferns, native violets, (not the common weedy one that takes over) jack-in-the-pulpit, bloodroot (Sanguinaria canadensis) woodland phlox (divaricata).......

For shrubs, consider mountain laurel, azalea, Rhododendron, Japanese andromeda, many beautiful viburnums, fothergilla...The list goes on.

There are a number of beautiful small-leafed dwarf Rhododendrons that do well in part sun.

When I moved here some of the branches on the pines were a bit low. I removed a few but only enough to allow me to walk beneath. Now there's a nice canopy there. Virginia creeper grows into the pines and makes a beautiful display of cover in the fall.

One thing that makes this part of my yard so beautiful and unique is all the pine needles on the ground. In the fall as the leaves are changing color, the pines drop their needles and make for a beautiful vibrant cover on the ground which I love.

Be patient and work with what you have. I'll bet you'll love this area in time.

Wish I could grow Cornus canadensis...... sounds like you have perfect conditions. Just how acid is " the horrible acidic soil"? Have you measured w/ a ph meter?