Like his Old Testament namesake, Rafael Corona is an angel, albeit an earthbound one who works his miracles in the desert of Palm Springs, California.Turn up Eisenhower Drive, and a mass of petunias, pansies, poinsettia, geraniums, begonias, dahlias and daisies will rise up before you, a riot of red and fuchsia, purple and pink, lavender and gold, filling the center aisle of the long cobblesto