The Next Miracle Tree: Tea Tree and Its Relatives

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Steven Foster is an herbalist, writer, researcher, and consultant based in Eureka Springs, Arkansas.

Trouble in the Everglades

America’s melaleuca story has a dark side. Of the many species of melaleuca, one, the cajeput tree or broad-leaved paperbark tree (M. quinquenervia), has become the nemesis of south Florida. Travel along any highway there, and you can’t help noticing the expansive thickets of eucalyptuslike trees with thick, peeling, papery bark.

About 1890, the United States Department of Agriculture (USDA) in Florida ordered cajeput seeds from France. In 1906, Dr. John Gifford, a Miami forester, obtained seeds. These seeds were planted experimentally in swampy areas of south Florida in the hope that the trees would dry out the soil sufficiently to make it usable for agriculture or housing. A secondary part of the plan was cajeput’s commercial development: it is an oil-producing plant, a source of decorative wood, and a fast-growing ornamental landscape plant.

In 1908, cajeput was being grown successfully at a USDA Plant Introduction Station near Coconut Grove, Florida. The station relocated a few years later, and the established cajeput trees stayed and reproduced. Like kudzu, cajeput’s growth characteristics and reproductive cycle, together with a lack of natural controls, allowed populations to run amok, and the tree is now a major ecological threat to important south Florida natural areas including Everglades National Park, Big Cypress National Preserve, and the Loxahatchee National Wildlife Refuge. Cajeput is more adaptable than was originally supposed; it thrives in relatively dry as well as moist habitats. It grows in dense thickets, eliminating most forms of native vegetation, and it has now invaded three of the four major ecosystem types in south Florida—saw grass prairies and mangrove and cypress swamps.

Early attempts to control cajeput by burning only exacerbated the problem. The tree’s thick, spongy, protective layered bark is resistant to fire, but even after being burned, the tree quickly resprouts. Fire also causes the hard, buttonlike seed capsules to burst open, releasing millions of tiny seeds which are then dispersed by wind and water. Florida’s Melaleuca Task Force, which issued a Melaleuca Management Plan for South Florida as recently as 1990, noted that “the uncontrolled expansion of melaleuca constitutes one of the most serious ecological threats to the biological integrity of South Florida’s natural systems.”

The development of commercial uses for cajeput has been equally unsuccessful, at least in Florida. The highly aromatic cajeput tree does produce an essential oil, but its chemical composition resembles that of eucalyptus oil more closely than it does the oil of M. alternifolia. Cajeput oil averages 40 to 65 percent cineole, and it has been used like eucalyptus oil as a stimulant, antispasmodic, and germicide as well as a fragrance; externally, it has been applied as a counterirritant for treating rheumatism, neuralgia, gout, sprains, and bruises, and has been inhaled for bronchitis and pneumonia. In the Far East, cajeput was planted for commercial production of the essential oil, which was used to treat cholera and diarrhea until it was replaced by more modern medicines. But the Florida cajeput populations have never been developed as a commercial source of essential oil, and probably never will be.

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