Blue gum (Eucalypts globulus), is a subspecies of the Eucalyptus. The broad juvenile leaves, borne in opposite pairs on square stems, are covered with a blue-grey, waxy bloom, which is the origin of the common name "blue gum". The mature leaves turn narrow, sickle-shaped and dark shining green. Blue gum was proclaimed as the floral emblem of Tasmania in 1962.

Blue gum is a tall, straight tree, growing up to 70 meters in height and 2 meters in trunk diameter under favorable conditions.The rough, deeply furrowed, gray bark is persistent at the base of the trunk but above this level it is shed in strips, leaving the branches and the greater length of the trunk smooth-barked.

The buds are top-shaped, ribbed and warty and have a flattened operculum bearing a central knob. 

The large creamy flowers appear in early spring or early summer, producing copious nectar which tends to yield a strongly flavored honey.The woody fruits shed numerous small seeds through the valves which open on the top of the fruit. These features are similar to other species of Eucalyptus.

Today's timber industry places a high value on blue gum timber - it yields pale, hard and durable wood. It has also been used for paper pulp and firewood, and its pollen and nectar is food for honeybees. Blue gum eucalyptus oil is used as an insecticide, a decongestant, a deodorant, and for antifungal and antibacterial use. It is also a food flavouring and a cosmetics fragrance.

Note: Although they have similar names, black gum is a deciduous tree that is originally from the United States and is not related to gum trees. The leaves of Black Gum emerge red in spring, and turn shiny green during the summer months.