Eucalyptus trees are part of a vast genus of flowering plants that are part of the Myrtaceae (myrtle) family. There are more than 700 different species of eucalyptus trees, most of which originate in Australia. The rapidly growing, mostly evergreen plants are notable for being some of the planet's tallest trees. Eucalyptus trees are grown in subtropical and tropical regions of the world, such as parts of North America, South America, China, the Middle East, the Mediterranean, Africa and Europe.
The vast majority of eucalyptus trees are evergreen. However, there are several tropical varieties that lose their foliage toward the end of dry periods. Similar to other species in the Myrtaceae family, the leaves of eucalyptus trees are entirely covered by oil glands. Mature eucalyptus trees feature foliage that is usually petiolate and lanceolate. The deep blue-green leaves tend to have a glossy or waxy texture.
Eucalyptus trees are known for growing very quickly. In many instances, eucalyptus trees can shoot up to 6 feet in just one year. The average mature height for a eucalyptus tree is around 40 feet, while mature width is usually between 10 and 12 feet.
Eucalyptus trees produce flowers. The flowers are distinctive due to their fluffy-looking stamens. The stamens can be yellow, cream, white, red and pink. The flowers do not have any petals, but are often decorated by showy and brightly-colored stamens.
Eucalyptus trees bear woody fruits that are shaped like cones. The fruits consist of valves on the ends that break open to release its seeds. The fruit is strongly scented, and is only edible by certain types of animals, such as cockatoos that have prominent beaks.
Though eucalyptus trees are generally extremely hardy, there are some pests that occasionally can bother them, including eucalyptus gall wasps, longhorn borers, lerp psyllids and several varieties of leaf-eating beetles. The majority of pests can be controlled by an application of insecticide, as well as frequent pruning of the trees.