Unfortunately there isn't a blue Brugmansia, but this is the next best thing!  Iochroma australis is a rare Brugmansia relative with miniature blue Angel's Trumpet flowers.  This 6 ft bush from Argentina becomes covered with 2 inch blooms from mid to late summer.  In full bloom, it is truly spectacular!   Toxic. Grow in sun or part shade in a sheltered position. Hardy to -5c.