My parents are looking to have some color along the east side wall of their house (zone 6 but close to 7). The area gets morning sun but is fully shaded by mid-day (as early as late morning in spring and fall). Normally their area has a lot of clay, but it so happens this plot has great soil due to many years of decomposing leaves and mulch.
My parents need plants that are relatively low-care, since they're novice gardeners. They don't mind watering, staking, etc. But lots of pruning, deadheading, etc would be a bit much.
I was thinking an assortment of lilies would look nice and give several weeks of color. Could they handle that amount of sun?
Wow, that looks beautiful! I had thought about hydrangeas but hadn't quite decided.
I'd been thinking about dahlias for the front (south side) of their yard. Only problem is I don't know if they'd dig them up to store over the winter. But I just love dahlias (and my own yard is far to shady for them).
They have some way-too-crowded hostas in the yard. I could probably dig and divide, so that's a great idea.
Just buy a few bags from Home Depot or Wal Mart and don't fret about having your parents dig them up in fall. They may want more sun that is available in that spot.
Hydrangeas come in all sizes so check the eventual size first. If you select one that blooms on new wood then size wouldn't be a problem since they could be cut back and still flower.
Dividing hostas while they are in the ground, using a sharp knife or a saw, if needed, and cutting out wedges (like a pie) is the easiest way for me to divide large old clumps and doing it as soon as they emerge in spring would be ideal. Try not to wait until the leaves have unfurled - that makes it much more difficult. Use compost when replanting and for the vacancies you've created with the pie wedges to provide some nutrition.
Astilbe is another huge family of plants that enjoy the shade and look lovely.