A tall evergreen with large bands of shedding bark and bluish green, highly aromatic leaves, eucalyptus globulus is the most familiar of the more than 600 eucalyptus species. The species is native to Australia and is commonly cultivated in Europe, Africa, India, and the Americas, including the southwestern United States. Long before it was carried to the West during the 19th century, blue gum was valued in traditional Australian Aboriginal medicine.
Common Names: Blue Gum, Eucalyptus, Fevertree, Southern Blue Gum, Tasmanian Blue Gum
Description: Evergreen tree, 50 to 80 feet tall, with large bands of shedding bark and bluish green, highly aromatic leaves
Hardiness: To Zone 8
Parts Used: Leaves
Range/Habitat: Native to Australia, naturalized in North and South America, southern Europe, Africa, and India
Also known as fevertree, blue gum played an important role in halting the spread of malaria in several countries during the 19th century. Planted in mosquito-infested marshes, the trees dried out the swampland through their heavy feeding, destroying the mosquitoes’ breeding habitat. Researchers have also discovered that eucalyptus oil contains a compound as effective against mosquitoes that carry and transmit malaria as 20 percent DEET (N,N-diethyl-meta-toluamide, an active ingredient in many commercial insect repellents).
The tree’s leaves contain eucalyptol, an active ingredient in over-the-counter chest rubs used for colds. Inhaling the vapor of a few drops of eucalyptus essential oil placed in boiling water can help clear sinus and bronchial infections.
With antiviral and antibacterial properties, essential oil of eucalyptus can be used to treat diseases such as flu, measles, and typhoid, and as an analgesic, anti-inflammatory rub for muscles and joints. Cooling on the skin, diluted eucalyptus oil also can be used topically to treat insect bites, stings, wounds, and blisters. Eucalyptus oil is used in mouthwashes to treat bad breath, plaque, and inflammation of the gums.
Caution: Never ingest pure eucalyptus oil, and always dilute it before applying it to your skin. Eucalyptus should not be used by those with severe liver disease, inflammatory disease of the bile ducts or gastrointestinal tract, or by children younger than 2 years old. Additionally, eucalyptus preparations should not be used on delicate areas, such as near the nose or eyes.
Eucalyptus is used to make paper. High-quality honey is made from the nectar of some species of eucalyptus, and the didgeridoo, a traditional Aboriginal wind instrument, is made from eucalyptus stems that have been hollowed out by termites.
How to grow it
Eucalyptus trees grow quickly in areas with warm summers, temperate winters, well-drained soil, and abundant sun. In Zone 7 and colder, grow eucalyptus in a greenhouse where temperatures remain above 50°F. Avoid overwatering; too much moisture causes the leaves to blister. Harvest the leaves before the tree flowers.