Wandcrafters
Makers of Fine Wands Since 2007
Bellatrix LeStrange's Wand

I actually find Bellatrix LeStrange's wand to be oddly chosen.  Walnut, which is metaphysically "safe" and overwhelmingly positive, seems particularly ill-suited to her.  Now if the wand had been Padauk, with its chaotic, sometimes uncontrollable energy, I would have understood.  Perhaps you can find Bellatrix in this description, though:

Walnut with Dragon Heartstring – 12 ¾ inches

Walnut is the wood most associated with Elves, and like the Elvin race, is considered timeless and immortal.  It is sacred to Zeus, Jupiter and Thor.  It has healing powers and promotes a long and healthy life.  Walnut thrives wherever it grows, helping the user adapt to any situation.  It averts lightning and protects against poison, especially snake venom, broadly protecting the user from danger.  Walnut harnesses the power of the wind, and encourages the user to learn, accept new perspectives, find inspiration, and think creatively and intuitively.  It blocks interfering emotions and promotes calm, clear thinking and focus.  Walnut blends reason with intuition and emotional awareness, enhances awareness of others’ feelings and needs, and helps the user to grow spiritually and heal from within.  It encourages good judgment, helps form positive intentions, and attracts the good intentions of others.  Walnut helps to smooth the path through life's transitons, turning dreams into reality regardless of change and challenge.  It promotes self-awareness and following the path of one's greatest personal energy.  Walnut promotes caring for the Earth and responsible use of nature’s gifts.  Its elements are Air and Fire.  In Common With:  J.K. Rowling.

Dragon heart string builds strength and courage, and is a powerful protection against danger and fear.  It confers energy, bravery and intelligence upon the user.  Dragon Sinew encourages wisdom, particularly in the use of scarce resources.  However, the user is cautioned against miserly and misguided hoarding of treasures, and is encouraged instead to expose their gifts to the light, and use their resources to enrich the lives of those whose friendship and love are greater treasures.  In Common With: Hermione Granger, Lucius Malfoy, Viktor Krum