Invasive Fig Trees in Miami
Anyone who's visited Miami in the summertime adores any large shade tree available to alleviate the sweating and discomfort of sun rays. Tropical fig trees, sometimes just called "ficus" in South Florida, are among the largest and broadest-spreading shade trees across the metro Miami area. Three species in particular create problems there, since their seeds quickly germinate and choke out native or other garden plants.
The laurel fig (Ficus microcarpa) remains the most invasive fig tree species in South Florida, according to the Florida Exotic Pest Plant Council. Laurel fig also goes by the names Chinese banyan or the Cuban laurel. This evergreen trees grows 50 to 75 feet tall and 40 to 50 feet wide and lacks any aerial roots from its lowest horizontal branches if soil conditions remain perennially dry. It does not buttress its trunk nearly as extensively as other banyan species, and thus has been historically favored as the fig tree of choice for yards and street plantings. The figs that develop attain a dark purple when ripe, with a diameter of half-inch.
The council tree, or false banyan or lofty fig (Ficus altissima), has not caused the same invasive disruption to South Florida's native ecosystems yet, but it remains on the Florida Exotic Pest Plant Council's list as a tree species to monitor. The potential for invasiveness exists on this spreading branched tree that matures to 70 or 80 feet. This species usually begins its life as a seedling germinating in the humus pockets on other trees' branch crotches or the boot scars on palms. The figs produced turn orange to red in color when ripe and are about half-inch in diameter. This tree grows tremendously fast in the heat and abundant rains and humidity of Miami, often lacking any aerial roots around the massive trunk.
Although the strangler fig (Ficus aurea) is native to South Florida, Kirsten Albrecht Llamas, author of "Tropical Flowering Plants" and a resident of Miami, says that it still can attain an invasive tendency in garden settings. This fig species gains notoriety and its name by first sprouting upon another tree's branches or the stem boot scars on cabbage palms. It then quickly grows a snake-like and extensive root system down the host tree's trunk to the ground. While the strangler fig doesn't strangle the host tree to death, it does out-compete it for sunlight and nutrients. This eventually finds the strangler fig much larger and dominating. Watch for strangler fig seedlings in gardens and trees, and remove them when small to prevent the demise of ornamental trees. Strangler figs grow 50 to 60 feet tall, but spread amazingly to two to three times that across a landscape.
- Florida Exotic Plant Pest Council: 2009 Invasive Plant List
- "Tropical Flowering Plants"; Kirsten Albrecht Llamas; 2003