God’s crayons sometimes come in newer colors. Unknown in T.H. Everett’s time when he wrote his 1981 The New York Botanical Garden Illustrated Encyclopedia of Horticulture, Caryopteris divaricata ‘Snow Fairy’ is a kind of Caryopteris with ornamental foliage in addition to the Caryopteris available at the time.
Marbley white and green foliage adorns ‘Snow Fairy.’ About the size we cherish for azaleas, boxwood, and Forsythia for small medium hedging, ‘Snow Fairy’ is a workable block size. And while its blue flowers flowering later in the season would exclude it from a white garden, it already has so much to offer and now more, and Everett encouraged Caryopteris use in general, “Summer- and fall-blooming shrubs are too scare to for gardeners to neglect any that hold promise...” so with ‘Snow Fairy’ we moreover shouldn’t feel picky.
Other Caryopteris also have blue flowers, which may match their sometimes greyish foliage, so perhaps their place in an all blue garden could be a plan.