Java plum
Java plum (Syzygium cumini) was first introduced to Florida in 1911 by the US Department of Agriculture for its edible fruit and ornamental qualities. It has since escaped cultivation and become invasive in south Florida, displacing many native plants. This tree is mentioned in many Eastern religious texts as providing deep shade for contemplation. All parts of the plant are used in Eastern folk medicine. Many South Florida blogs have written extensively on using the fruit for recipes. Java plum is not prohibited in Florida, but the Florida Invasive Species Council (FISC, which was formerly FLEPPC) lists it as a category I invasive, indicating known negative ecological impacts. UF/IFAS first assessed Java plum in 2003 and then most recently in 2021 and has concluded that Java plum is invasive in South Florida.
Family: Myrtaceae (Myrtle)
Habit: Fast-growing and long-lived evergreen tree that may reach 100ft in height but often supports multiple stems from a short primary trunk. The lower bark is coarse and discolored while newer growth is smooth and gray.
Leaves: Opposite, simple, entire, elliptic to broadly oblong, smooth, glossy, and leathery from 2 to 5 inches long with short, pointed tips and 1-inch-long petioles. The midrib is prominent and yellowish with lateral veins that are closely parallel.
Flowers: Inflorescence is typical of members of the Myrtle family with numerous pronounced stamens. Flowers are white or pink with short petals fused into a cup approximately one half-inch in diameter. Flowering occurs from late spring to summer, and fruit matures by late summer.
Fruit: The fruit is an ovoid, 1-seeded berry that is slightly less than one inch in length, turning from green to pink to deep crimson and finally black. Wildlife readily consumes the fruit, but the fruit can also be eaten raw or baked into desserts.
Distribution: South Florida to Volusia County on the Atlantic coast and Pasco County on the gulf coast.
Java plum’s fast growth and dense canopy enable it to shade out native trees and shrubs in Florida’s hammocks, pine flatwoods, and well-drained uplands. Fruit-loving birds and other animals, such as wild boar, consume the fruits and may facilitate spread. The fruits may also become a nuisance if they accumulate beneath the canopy as they my rapidly ferment, emit a foul odor and attract swarms of flies.
UF/IFAS does not recommend the propogation of Java Plum. Avoid its use in landscapes and replace it with native or non-invasive shade trees.
Hand-pull seedlings. To prevent new seed production, remove saplings before five years from establishment as they take approximately five years to reach sexual maturity.
Use chainsaws on mature trees. Grinding the stumps will prevent resprouting. If stumps are left in place, it is best to integrate a cut stump herbicide treatment as untreated stumps will normally resprout prolifically.
There are currently no biological controls available for release.
Cut stump treatment with a triclopyr product is generally effective. If trees can be left in place, the reduced hack and squirt technique is extremely effective. Apply one ml of a 50% solution of aminocyclopyrachlor to one hack per 2-4 inches of stem diameter. Basal bark treatments with 20% triclopyr products or 6-9% imazapyr may be effective on trees less than 4-inch in diameter. Foliar treatments with triclopyr are most effective on seedlings and saplings but resprouting from the root collar is highly likely. The addition of a methylated seed oil adjuvant is recommended to facilitate herbicide penetration through the waxy leaf cuticle. Follow-up treatments for new seedlings and resprouts from stumps should occur within 2-3 years.
