What kind of roses grow best in a shady area?

Roses will grow in this level of shade but tend to have problems with pests and black spot. They may also get "leggy". You will want to be careful with how often/how much/when you water to minimize diseases.

Not knowing you specific climate, I would ask at a your local nursery for suggestions. Newer varierities are bred to be more disease resistent but this tends to be at the cost of scent. Also, be aware that not all roses bloom continuously through the summer, some varieties bloom once or twice only.