I planted a beautiful tsuga to be a screen between my yard and the alley. It's a Canadian hemlock or tsuga canadensis "Gentsch White."

I planted a tiger-eye sumac near it, for the same purpose. The colors are terrible together, so I'm thinking about what plant could replace the sumac. I've got a dentana viburnum "blue muffin," a red osier dogwood, and a viburnum lantana "variegata" in the yard as well. All of these are small and could switch places with the sumac. Or I could go for something completely different.

Also, while I'm waiting (years and years) for the tsuga to actually be large enough to serve as a screen, are there tall annuals that would look nice with it?

The 6 square feet around the tsuga get sun from pretty early in the morning until about 1 p.m. The 6 square feet around the sumac get lots of midday sun. The soil is healthy; not too wet, not too dry. Any advice?