Paederia foetida (Skunk vine)
Paederia foetida is in the Rubiaceae family and currently on the Florida Noxious Weed List and on the FLEPPC’s Category I list of invasive plants (MacDonald et al. 2008, Wunderlin and Hansen 2008). Native to Eastern and southern Asia, the vine was introduced to Hernando, Florida in 1897 with a prospect as a fiber crop (MacDonald et al. 2008). It expanded beyond its intended purpose and invaded natural areas becoming a nuisance in central and north central Florida (MacDonald et al. 2008).
Like many other invasive species, skunkvine thrives and adapts to many habitat types such as a hydric hammock, but also in other hardwood communities, mixed, pine forests, sandhills, marshes and floodplain forests (MacDonald et al. 2008). P. foetida can actually kill other vegetation and native species by breaking off tree branches with its heavy added weight and by eliminating resources such as sunlight or nutrients when it becomes too dense in understories (MacDonald et al. 2008).
The woody vine gained its name from its “foul smelling” odor when crushed, hence the origin “foetida” (MacDonald et al. 2008). The smell comes from sulfur containing compounds present in the vines’ leaves. Paederia foetida lacks thorns, but makes up for this with its extensive growth. It can grow up to 30 feet into tree canopies or along the ground, always twining to the right (MacDonald et al. 2008). Leaf blades may vary in size, but are arranged opposite and have cordate bases, pointed tips with an entire margin. Although uncommon, leaves may be found arranged in whorls. Petioles are two to three inches long. Flowers are lilac with red centers and are small in size (MacDonald et al. 2008). Fruit are also small, shiny, brown, spherical and contain two seeds. The seeds are one mechanism of reproduction for P. foetida in addition to vegetative reproduction via stems rooting into the soil (MacDonald et al. 2008).
Management tactics include preventative, cultural, biological and chemical methods. Because of regrowth, mechanical methods are often impractical. Preventative and cultural methods include providing a natural biodiversity that doesn’t allow the vine to take root and being aware that the vine is not able to propagate via regrowth when disposed of (MacDonald et al. 2008). Biological control agents have been identified from Japan and include leaf beetles, two sawfly species, a stem gallmaker and moth and a flea beetle. The flea beetle shows the most promise as a biocontrol agent because it feeds on the vines’ root system which prevents the vine from obtaining nutrients and water (MacDonald et al. 2008). Chemical control of the vine is encouraged as an efficient mechanism, but often requires multiple applications to effectively stop any regrowth. Recommended chemicals include Roundup (glyphosate) or triclopyr and application should be applied so as to only target the vine and not the vegetation it is growing on (MacDonald et al. 2008).
Links:
http://plants.ifas.ufl.edu/node/303
http://plants.usda.gov/core/profile?symbol=Pafo3
http://www.florida.plantatlas.usf.edu/Plant.aspx?id=1466