I am currently rereading Dragonfly in Amber. There is a scene in which Roger tells Brianna that both the white rose and the white heather were the emblems of Bonnie Prince Charles. I decided to investigate more about white heather, and this is what I found.
White heather is especially sacred and magical and brings good luck. It grows only on the grave of a Fairy or on ground where no blood has ever been shed. Heather tops should be gathered at dawn for greater magical potency (Evert Hopman, 147).
Basically this plant represents exactly what the white colour means in the Cherokee shamanistic system (peace, happiness). The white heather has a strong association with Claire, who is known as White Raven by the Amerindians. In fact Nayawenne in Drums of Autumn mentions that the stone associated with the white raven in her dream is a sign of strong magic, the power to heal. Frankel states that ravens with white feathers “were a good omen of blessing and spiritual cleansing” in Celtic lore (141).
I am currently working on another post. It is about book 2 and it will be published soon.
Sources
Evert Hopman, Ellen. Scottish Herbs and Fairy Lore. Los Angeles: PENDRAIG Publishing. 2010. Print.
Frankel, Valerie Estelle. The Symbolism and Sources of Outlander. Jefferson: McFarland & Company, Inc., Publishers. 2015. Print.