An Invasive Species: Tree Privet (Ligustrum lucidum)
Keep your eyes open for this Category 1 FLEPPC invasive species. When the Florida Exotic Pest Plant Council deems a plant a Category 1, it means that the plant is capable of altering native ecosystems by displacing native species. Other common names for this Ligustrum include glossy privet and wax-leaf ligustrum, which are
fitting descriptions of the large, shiny leaves arranged oppositely on the stems. Belonging to the olive family (Oleaceae), this small tree can grow to 10 m tall and form a dense shady canopy above the forest understory. It has been documented in several Central to North Florida counties and has also escaped in Pennsylvania, Virginia, North Carolina, Texas, Georgia Alabama, Mississippi, Louisiana, Maryland, California and Hawaii, as well as other countries (K.A. Langeland, et al. University of Florida-IFAS Pub SP 257, 2008).
The typical growth pattern often involves multiple trunks with very smooth bark and twigs being dotted with
numerous corky lenticels. Once a parent plant is established it will produce copious clusters of dark drupes that will blanket the understory with small seedlings in a short time due to very high germination rates. Birds are a likely dispersal mechanism also. It prefers a mesic hardwood hammock setting in N. Florida and when cut down, readily re-sprouts with many new stems from the trunk. An herbicide application to stumps is a must for control. These plants can gain an advantage in many ways in our native habitats. They tend to be salt tolerant and are able to withstand fire well. They can grow in acidic to alkaline soils but do not do well in wet soil conditions. They will commonly colonize river banks though where the higher levees provide a deeper, sandier footing.
There are two other non-native ligustrums established in North Florida also but they are easy to separate if you look closely at the foliage. The plant commonly called Chinese ligustrum (l. sinense) has much smaller leaves. The more similar looking Japanese ligustrum (l. japonicum, also called wax-leaf privet), can be distinguished by the lack of a thin translucent margin along the leaf edges. This is easy to see if you hold a tree privet leaf against a backlit setting.
The photographs taken for this article are from Wakulla County in the middle Panhandle of the state. The shrub is rapidly becoming a dominant species in the understory of this woodlot.