Sounds like you've got "part sun" or a shade garden.
Head to the 'shade section' of your garden center for appropriate plants. Here's one a friend of mine did:
Perennials like Hostas, astilbe, bleeding hearts, helleborus, ferns - stuff like that. In zone 8 it's hot, so you'll need to water often.
Annuals like begonias, maybe impatiens can take it...
Really if you go to a good garden center, they'll know what works best in your area. Once you pick what should be there, you can make your plan and shop around for the best prices. Tall stuff in back, lower stuff in front.