Depends how big the hedge is and how much shade the bed that you want to grow in is. Also how wide the border is and and how near the hedge you want to plant. If its a newly planted hedge don't plant anything very near it for a year or two anyway until the roots are well established.
If you want a bit of colour try using containers for now.
There are a few things that would survive close up but they don't have large bright flowers.

A photo would help.