You might want to look into Bird of Paradise which can grow quite large, albiet "slowly". If it reaches for sunshine it might disappoint you as a centerpiece. These are related to banana plants. You can plant some gardenia. but 8x8x10 is a large area to be shaded, so it will probably get some summer sun. Unless this area is COVERED you should think about summer sun. Norther exposure doesn't equate to shade in my home. If it is UNCOVERED and will get some hardcore sun during the summer, any shade plants are out. Ferns will get toasted. Which is why I suggested Bird of Paradise.

A centerpiece would like great in that type of area, with some shade lovers underneath. Personally, if MY area fit the bill, I'd LOVE to plant a couple Japanese Maple.

Ideally, we would have a spot like yours which gets direct sun during the winter and very little during the summer. That would be so nice. Good luck.

Here is a link that might be useful: Japanese Maple in Hot Climate