Answer: Here are a few suggestions for shrubs: hydrangea, witch hazel, snowberry, spicebush; perennials: hosta, astilbe, coral bells; annuals: impatiens, coleus, monkey flower: bulbs: caladium, tuberous begonia (both these need to be lifted and stored for the winter, as they are tender bulbs), and lily of the valley (can become invasive). Ferns are also a great choice for woodsy, shady spots.
I think it might be difficult to sow any seeds this fall, at least until you plant the larger components of your design. The perennials probably won't blossom next year if you sow the seeds this fall. It's probably better to 1) start the seeds indoors under lights quite early next spring, so you have transplants to place in the beds, or 2) purchase your plants from a nursery. Enjoy the planning and planting!
Q&A Library Searching Tips