Another thing you might do is google 'stack 'n whack quilts' or '4-patch posy quilts', check the images and see which sashing choices appeal to you. This is also a great way to get an idea of the effect your choices would have.

I would go with navy blue. It isn't in your print, but would go with all of your colors, and not compete with the blocks.

This is a 4 patch posie, right? Not a stack n whack.....there are more sections to that pattern...maybe....

color of sashing.....definitely dark to give the eye somewhere to rest, and make the patches pop! On point would be interesting too, like looking thru a lattice at a field of flowers.....

I would go with white to make your lovely blocks pop.

I agree with the dark green in the leaves.

I am sure it will be beautiful no matter what color you choose. I try to use a darker color that is not in the print.

Personally, I would go with a dark color. Green or even black. I think it is far more dramatic than white or pastel. Of course I would have to audition it first just to make sure that I didn't spoil a beautiful quilt.

I agree-yellow gets my vote!

I think white stashing would make your beautiful blocks stand out, then a 2.5 to 3" border, then a border of the fabric you used for stack and whack if you have any left. It's a beautiful quilt.

I would take the four different blocks and see how they audition on a sheet or yardage you may have in the different colors. It would give you an idea of what would look best in your opinion.