I would normally say us the gray, but....
This time I TOTALLY vote for the MULTI-COLOR border using the colors in your quilt. I really think it would make your quilt pop, since you have neutral colors around your brighter colors.
Love your quilt! :)

I vote shadow fabric.

I think a narrow (usual) would be fine on this quilt.

I vote for the shadow color. But, if you do not have enough of any color, DeltaMS has a good suggestion about piecing all the colors. I do that, especially, when I make a scrappy quilt. Good luck....be sure to post a picture.

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*** Shadow
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I would vote for the darker gray but if you don't have enough I think you could possibly sew strips together with the lighter color and gray. Anxious to see what you decide. Lovely quilt.

I love the shadow on half to mimic the blocks idea for the binding. I love the quilt also! Nice job!!!

Awesome quilt Kitsie. I think the shadow fabric if you have enough but I also like MadQuilters idea. Please post when you finish.

How about fat binding with the off-white background fabric and a gray (shadow color) flange?