Since your pattern is crosswise, just try cutting your border a little shorter (be sure to measure carefully & get both sides the same length) and then "ease" the quilt onto the border. It will help considerably. And you might try dampening your borders & stick them in a hot dryer for a few minutes. That might shrink it back into shape.

I have wavy borders quite often and when it is quilted they are not noticeable. Yours do not seem very severe and I have had some pretty bad ones turn out fine when quilted.

Do you cut your fabric length wise or across the width of the fabric? I have less trouble if cut across width of fabric even though I have to piece the borders strips to be long enough.

Your quilt is so pretty and unique. I have problems with wavy borders also. Mine can usually be smoothed out using the basting spray and smoothing, smoothing, smoothing. It quilts pretty good using a stippling type of quilting. - Cynthia

I have never had wavy borders. I fold my quilts in half, lay the border piece on the fold and gently run my hand down to the other side, cut border there, lay it on top of other border piece and cut it to that size. I pin the top edge in half and each side of the pin in half, do the same with the quilt and pin both together and when sewing together I hold at the pins and if long, I hold it out and hold between the pins and make sure the pieces stay the same size. Then I do the same for the sides. I don't like square corners on my quilts so I don't miter, I round the corners using a plate to round them off. Could be you could just redo the miters and take up the fullness that way.
Don't stop trying, just keep making quilts and you will eventually get them right. Get a book that shows how to do borders and try that.
Your quilt is beautiful and I can see all the work you have put into it.

Don't give up. If you go to Bonnie Hunter's web site quiltville.com she has great instructions for measuring your borders, and even a crooked quilt will have nice flat borders.

That quilt looks fantastic to me,
Where is the problem. ??
I love it.
Marlene.

do you have some of the border blocks on the bias. That could be the problem. Or when you pressed you accidentally stretched the fabric.

It's gorgeous!!! Perhaps you can slightly fold the material and sew a seam down the horses that have the straight lines on the outside of them? Do this ever so often and it should get the wave out? Hope I explained this right.

I had the same problems when I first started quilting...determined that when I ironed my fabric, I was stretching it...ironing it too hard. So when I started just pressing my seams lightly (setting the seams), I didn't have this problem anymore.