Melaleuca in Florida: A Literature Review on the Taxonomy, Distribution, Biology, Ecology, Economic Importance and Control Measures

Melaleuca (Melaleuca quinquenervia (Cav.) S.T. Blake) is a large tree species that occurs naturally throughout eastern Australia, New Caledonia, Irian Jaya and southern New Guinea. In North America, melaleuca has primarily infested the Florida peninsula south of Lake Okeechobee. It is classed as a Federal Noxious Weed in the United States and as a Prohibited Aquatic Plant and Noxious Weed in the state of Florida. In the continental United States, melaleuca has been recorded from Louisiana, Texas and California. Additionally, this tree has become moderately invasive in Puerto Rico and Hawaii. Melaleuca rapidly invades moist, open habitats, both disturbed and undisturbed, and forms dense, impenetrable monocultures. In general, invasion is less prominent in forested sites than marshes; however, only dense hammock-type communities seem to produce enough shade to prevent invasion. Invasive characteristics of melaleuca include its evergreen habit, prolific seed production, frequent flowering, and flood and drought tolerance. This tree threatens biodiversity of native flora and fauna by diminishing the value of their habitat. The large expanses of melaleuca on public lands have cost public agencies in Florida $25 million in control efforts between 1989 and 1999. Estimations of economic impacts of melaleuca on recreation, tourism, fires, loss of endangered species, and more range from $168 million annually to $2 billion over a period of 20 years. Various methods of control (chemical, mechanical, manual, biological and integrated) are evaluated.