The most natural thing would be a combination of asters and goldenrod. Around here, a pair of shade-tolerant species grow together in conditions like you describe. In fact, if you do nothing, they will probably appear on their on. Asters and goldenrods grow together in association all over this continent--there are dozens of species of each, and when something is so widespread, you can bet it's wildlife friendly. This solution is probably not as showy as what you had mind, but these plants are carefree, very pretty, and very good for the environment.

Shade-tolerant asters include A. lateriflorus, A. macrophyllus, A. ptarmicoides, and A. shortii. Shade-tolerant goldenrods include S. flexicaulus and S. caesia. All are available from Prairie Nursery.

Thanks. Exactly what I had in mind!
I appreciate your input. Take care & God Bless!
JD