I use a SITD foot. Handy little tool! When I tried with a walking foot, I couldn't see where I was going. When I have a panel quilt, I SITD around the panel first, then quilt around the features in the panel with machine embroidery thread. Those green boughs on the trees could be almost thread painted. A loopy meander would do for the rest for me. I dislike doing SITD and haven't mastered much besides flowers and this quilt wants no flowers. I would SITD on both sides of the brown border and do a loopy linear pattern in the green border. I like leaves on a continuous vine.
Very pretty and well designed quilt.