The Blue mallee, or Blue-leaved mallee (Eucalyptus polybracteaalso formerly E.fruticetorum) is a small multi-trunked sclerophyll tree that grows naturally in western New South Wales around West Wyalong and in Central Victoria Whipstick Scrub north of Bendigo and similar patches of mallee at Inglewood, Wedderburn, Wychitella, St. Arnaud, Rushworth areas in Victoria, Australia. 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 grey-green. Flowers are followed by woody capsules 3–6 mm long.
E. polybractea leaves are used to produce eucalyptus oil with very high levels of cineole (up to 91%), yielding 0.7-5% fresh weight overall. The oil is primarily used medicinally and for flavoring.