The Eucalyptus robusta grows throughout southern Florida. It has naturalized easily in the region. Native to southeastern Australia, the tree prefers tropical locations. In the tree's native habitat, it flourishes in swamps and lagoon shorelines.Known as the swamp mahogany, the tree grows to a height of 180 feet but species have been known to attain a height of 260 feet, according to Auburn University.
The Eucalyptus robusta was first introduced into Florida in the 1880s, according to the World Agroforestry Centre. The tree grows rapidly, so it was considered to be a suitable candidate for timber plantations. It was also widely planted in the state as a windbreak. The tree also holds value as a pulpwood.
The wood of the Eucalyptus robusta is similar in appearance to hickory. It has a heavy weight of 46 lbs. per cubic foot, according to the U.S. Forest Service. The wood offers acceptable resistance to fungus. The attractive heart wood in the center of the tree is resistant to insects and termites. The wood is widely harvested and used for poles, flooring and fencing.
In southern Florida, the Eucalyptus robusta will tolerate a light frost occurring for a short duration, but it will quickly succumb in freezing weather. The state offers 52 inches of rain annually which the tree thrives in. It also tolerates the region's sandy soil and inadequate water-logged conditions. Florida has a seasonally high water table that does not appear to affect the tree's root system.
Flower and Seed Production
From September to November, the Eucalyptus robusta produces abundant blossoms in Florida. The cream-colored flowers have five to 10 axillary umbels. The stigma of the flower is surrounded by filamentous stamens. The flowers are pollinated by insects. Following pollination, dark green capsules are produced. Each capsule measures 1/2 inch in length and contains several seeds. The capsules ripen over the course of seven months before the seeds are released. In Florida, the capsules are slow to release their seeds and often stay on the tree for up to a year. Flowering and seed production begins when the tree reaches three years old.
Growth in Florida
In Florida, the Eucalyptus robusta is usually container planted in select locations. The ideal time to plant the young trees in the state is from mid-June to mid-August, according to Discover Life. The tree produces distinctive aerial roots that grow outward from the tree's trunk at a height of up to 20 to 40 feet and reach downward into the soil. This gives the tree an unusual trunk appearance of the twisted, woven roots. The root system makes the tree wind resistant. The aerial roots are rarely seen in the tree's native habitat.