I planted viola odorata and viola duchess du parma in my garden 2 years ago in a spot with bright shade with little direct sun. They sustained some slug damage the first winter and spring, but once I put out some slug bait (only for my violets would I do such a thing!), they looked a little better, with more and larger leaves and a few flowers. Unlike in the garden at my old house, these violets seem to not be spreading at all, and they don't flower much. The plants just don't look very vigorous. Last spring (a year ago) I top dressed with a good thick layer of compost, but the plants didn't seem that much happier. Do they need more sun? More water? Is my soil missing something? The foxgloves and dicentra that grow nearby seem fine. Are they just still recovering from being so slug chewed??

Thanks for any help!