They always follow the lilac, snowball viburnum
That bush is beautiful. In my yards it's red honeysuckle and the wild Crested Dwarf Iris (Iris cristata).
Lilo, they do look like snowballs, what neat flowers. I've not seen white viburnum, before. In this area, they have pinkish flowers and they don't have the ball shape that the white has.
You're reminding me of my childhood. They must be really prevalent in California, because that's about the only connection! The viburnum we had in our yard was so fragrant, are yours also sweet smelling?