It's lovely and no matter what you decide to do it will remain lovely!
I generally don't do a lot of quilting design work so I typically don't use a lot of white space. For me I'd trim the blocks down to 12" finished size and I probably would use 2" sashing. I'd probably keep the sashing print and only the sashing square background. The yard you have left is probably enough (did some rough math in my head) for either a border or sashing. I'd consider buying some similar colored/patterned fabric that is an opposite color from your border yardage (so if you have green use pink or yellow etc.). Seems like no matter how much fabric I have I can always use a little more...
One thought I had if you bought some additional fabric to sash with and used the yard you have for the borders is to make a single hex for each of the sashing squares out of the border fabric, putting it on the background fabric. Not sure what size your sashing would need to be to accommodate that. It would probably be simpler and you would probably still have enough fabric to make the sashing squares out of the border fabric.
Last edited by Iceblossom; 10-08-2018 at 10:37 AM.