Shelley's correct. In order to have a wide binding, you have to have a nearly equal width of quilt edge to support it. Then the folded and mitered corners will work. I've done an inch easily. I'm not sure about wider.

Check this site out.! Sharon has video and she goes step by step on many different things. Click classes then free class and it will bring up many of her videos. She does lots of quilt shows and talks about how important the corners are and how the judges will use the clipboard or paper to make sure they are done right.

http://www.sharonschambernetwork.com/

Great Job on yours I Love it.!

Beautiful quilt!