I like lilacs, hydrangeas, but welcome other suggestions. Because of the shade, I'm not sure lilacs would work, but one never knows. That's why I'm seeking help. [Also like the butterfly bushes, but I think they require full sun...maybe there are some that don't]

I prefer a shrub/plant that will flower at some point, but something with unique foliage would be okay.

Since this will be in a "corner", I would prefer that it be dense so that saplings have difficulty establishing themselves at the base of the plant.

Thanks for your help.

For something with unique foliage and the ability to be a major focal point, I'd consider oakleaf hydrangea, Hydrangea quercifolia. It has big, bold foliage that looks like giant oakleaves and that turns wonderful colors in fall. And it produces showy, large, white cone-shaped flowers and can become a large, spreading plant. Plus it has more interesting bark than any other type of hydrangea - kind of a cinnamon color and it peels off in strips (exfoliates).