Jane.
I'm in a similar situation here in 7B. Too many trees makes growing any kind of grass next to impossible. I have pachysandra terminalis in one area, but it doesn't spread quickly and just would work where I really need something.
Have you tried vinca/periwinkle? It spreads... fast, is evergreen and has small flowers in spring. There are a number of varieties, from plain green to gold edges.
Good luck.
