There's quite a list of perennials that will thrive in your shady site with low (acidic) soil pH. The list includes Anemone (A. quinquefolia and A. virginiana), Goat's Beard (Aruncus dioicus) Wild Ginger (Asarum canadense), Spring Beauties (Claytonia caroliniana), Shooting Star (Dodecatheon meadia), Woodferns (Dryopteris species), Flag Iris (I. pseudacorus 'Variegata'), other Irises (I. ensata and I. sibirica), Lily-turf (Liriope muscari), Bird's Foot Violet (Viola pedata), False Solomon's Seal (Smilacina racemosa), Maidenhair Fern (Adiantum pedatum), and some Phlox (P. stolonifera and P. adsurgens). This list may look overwhemling, so I'll tell you which are my favorites. Goat's Beard tops my list. There is a spectacular, airy-looking standard form and a darling, delicate-looking dwarf form. I love Wild Ginger's dark green glossy leaves, and the clump spreads wider and grows more gorgeous every year. Spring Beauties are tiny woodland wildflowers that pop up in spring and then disappear for summer, but their tiny white blooms with pink veins are real charmers. And finally, I love False Solomon's Seal for its arching growth habit, blooms that resemble Astilbe, and late-season red berries that the birds adore.