I currently have a few Corydalis lutea growing in the midst of my hosta's. The luteas will grow from seed so where I had one I now have several. :) Pretty day lilies! :)

The corydalis lutea is a plant suggested to me in another thread as a free seeder but not invasive, so I have plans for it next year. To see others in the list of suggestions, check the link below

Here is a link that might be useful: Free seeders to go with hostas

I have a few Corydalis. My favorites are a white variety with fragrant flowers and a Heronswood selection "Blue Heron"

Here is a picture from today with Corydalis "Blue Heron", Hosta Olive Bailey Langdon , primrose and Hakonechloa macra Aureola grass.