Yarrow essential oil, Achillea millefolium, high in azulene, is a deep blue oil that is often used for its anti-inflammatory and astringent properties to relieve itching and swelling due to insect bites and dry skin conditions. Rich in flavanoids and amino acids. It is also helpful for wounds, oily hair and scalp and for hemorrhoids. Yarrow essential oil is also known to encourage hair growth.