I am building a screen on a longish strip of property -- east side of the house. I need to block my neighbor's house. I already have a large, old Norway spruce, a horse chestnut (in front of the spruce -- lovely) and a blackhaw viburnum. I love all of these plants!

I need something just north of the Spruce/chestnut (12 ish feet from trunks) and 6 or 7 feet to the west of some arborvitae on the neighbor's property. I want a deciduous something that gets to be about 15 - 20 feet tall, has spring flowers, and fall color. It gets some nice mid-day sun but is shadey in the early morn and mid to late afternoon. I was thinking of either a Pagoda Dogwood (have one in the front yard and it's a beauty) or a Rainbow Pillar Serviceberry. You will see the structure against the Arborvitae in winter --

I am in the western suburbs of Chicago.

Any thoughts? Other ideas?

Shadey

This year I think the shrub is not rusting noticeably (so far) but looks poor otherwise, as though it is going to peter out.

Maybe it is anticipating that I will probably yank it when I get around to it.