Cassiope fastigiata x C. tetragona v. saximontana - White 'Lily of the Valley' type flowers on a vigorous, upright shrub.  This one takes more heat than the others. Grows to about 8" x 12".  A choice and rare alpine plant.  Needs protection from the hot afternoon sun.  A key to success is keeping the roots cool in the afternoon.  They need good drainage as well.