Even with ideal growing conditions, I have found that Helleborus are slow to increase in size.
They also resent being moved, once they have become established in a location and may suffer a setback.

Best growing conditions are in rich, well drained, circumneutral soil, with part shade (morning sun) to bright shade. They are not a full shade plant, only shade tolerant.

If moved, late summer or early autumn is probably the best time, so that they become established before ground freezes.
Water well before and after moving, Dig as large a root ball as you can safely handle, to avoid disturbing the roots.

In your Zone, I would surmise that you have no worries about soil temperature, as we do here, during the summer.
I try to limit any moves or new plantings until the soil cools into the 60°F range or less.

Good luck!
Rb