I can't see enough detail to be sure, but my guess is Convolvulus cneorum. If so, it is an evergreen perennial native to the Mediterranean. It is more drought tolerant than the hydrangeas, and requires lean, well drained soil so it doesn't get root rot. Its leaves will be damaged by temperatures below 15º (zone 8b). Colder temperatures may not kill the plant, but it will require cutting back before new growth begins in the spring.

They are white New Guinea Impatiens. The picture becomes clear if tapped and then expanded.

Even without zooming, they don't have the silver foliage of C cneorum.