I find the best hellebore for dry shade is Helleborus foetidus. I have several growing under a very large beech and they do extremely well, while the helleborus hybrids I tried really struggled and required extra watering.

What most hellebore need is not so much dryness as excellent drainage, and in your zone (5) they will appreciate at least moderat amounts of sun. Once they are established, they will tolerate shade very well, but your flowering will be much reduced.

George

Mine are in a very dry area under tree--thriving where other things I have planted gasped and died. Bought quart size and they flowered the first year. What is really great is the flowers last for 2 months or more on the plants, which are evergreen. I'm hooked and am adding more in my other dry shady areas.

Thanks everyone! The bed will get morning sun in Spring before the trees leaf out. Sounds like it's worth trying, and I love plants that bloom long and stay nice looking after that.

Jen