What is the importance of "Ashes in Roses" in the novel, The Thorn Birds?

Ashes of Roses is the name of the pinkish grey hue of Meggie's first formal. It is while Meggie is wearing that dress, that Father Ralph realizes that she has become a woman and is in love with him. The color remains one of Meggie's favorites throughout her life. Ashes of Roses is also the phrase Father Ralph uses to express his sorrow, when he chooses ambition over love.