Layers ... I'm thinking a smaller, possibly multi-stemmed, understory tree to make the transition from the high canopy of the tree to the lower shrub and even lower herbaceous perennials. (It would also help screen the view of the neighbor's shed which is now nicely framed by aforesaid tree and shrub.)

agarden,
thanks for your input. That is what I was hoping to do so will have to start looking at ornamental trees to see my options. I have had an Amelanchier, Autumn Brilliance in for about 3-4 years in another part of the back yard....and although healthy it just seems like it won't grow! So, I'll have to look to others that might actually grow a bit faster and fill the area. I like the idea of 3 season interest.

Dont forget to include tall shrubs as a possibility. They can be grown like a tree.

The Black Lace can be pruned back, it will come back nicely.

I concur with the idea of blocking the view of the shed. I like viburnum dentatum for size, but don't know if it will get enough sun to fill out properly. Day lilies won't be tall enough to provide the balance that you need.

Competing with the roots of a silver maple is difficult, too. Listen to your local plant dealer.

Jim