The Blue Mallee, or Blue-Leaved Mallee, is a deeply rooted perennial tree in the Mallee regions of Victoria and NSW. The bark is smooth and fibrous near the trunk base. Leaves are disjunct and linear to narrow-lanceolate. Juvenile leaves are glaucous and adult leaves gray-green. Eucalyptus leaves are the favourite food of Koalas, and have been used as traditional medicine by the aboriginal peoples of Australia. Having the highest cineol and eucalyptol among the Eucalyptus, it continues to be used as a highly popular Essential Oil throughout the world today.