Improved yellow-leaf caryopteris. Sunshine Blue ® II caryopteris is a new, improved cultivar. It replaces the original Sunshine Blue ® caryopteris as it has proven in our trials to be brighter, hardier, and more adaptable. Vivid yellow foliage holds up to the heat of summer and offers bold, beautiful contrast when blue flowers begin to appear in late summer. Also known as blue mist spirea, despite the fact that it is not remotely related to Spiraea.