Welcome, Cheryl
and hope we can help you out. Nothing is "cut and dried" with gardening because there are so many variables. A picture of the area you want to plant would help us a lot.
Your zone 6 designation only tells us how cold it gets, on average, in winter where you are. Not how hot it is in summer, or if the air is humid or dry, or anything about what your soil is like, your altitude etc.
My daughter's garden is in Salt Lake City, UT which is also zone 6, so she has very arid conditions most of the time, high altitude which means drastic swings in temperature in the spring and fall, and clay soil for the most part. This will be drastically different from a zone 6 garden in, say, Pennsylvania or Kentucky.
If your yard is primarily shady, there must be trees around/over the planting area you're wanting to beautify. This complicates matters in that some plants can compete with tree roots, grow and thrive, and some just can't. I grow wonderful begonias under my huge oak trees here, but I have to keep them in pots, just sunk into the earth a bit, and covered with mulch so it looks like they are growing in the ground. They simply get eaten up and choked out by the oak tree roots if I plant them in the ground.
Again, what we recommend rather depends upon whether you're looking for a pretty, low maintenance ground cover with a little color, or a full-on high maintenance flower garden. Please let us know?
