Rubiaceae, the Madder Family
Paederia foetida and another tropical Asian species, Paederia cruddasiana, commonly known as sewervine, are very similar in habit, appearance and odor. The following description applies to both perennial twining vines. The plants are evergreen in South Florida, but deciduous in Central and northern Florida. Although skunkvine may develop a woody stem base and root system with age, the stems are generally slender and herbaceous, reaching up to 33 feet in length. The opposite (rarely in whorls of three) leaves contain sulfur compounds that give them a disagreeable odor when crushed. The leaf blades vary in shape and are borne on petioles ranging from ¼ to 3½ inches in length. As in all members of this family, the stipules are interpetiolar (located between the petiole bases). Skunkvine stipules are persistent, triangular to ovate in shape, and up to ¼ inch in length. The branched inflorescences may be axillary or terminal. The flowers are small (approximately ⅓ inch long) and tubular with five short spreading to reflexed lobes. They may be pinkish-white, grayish-pink or pale purple in color with a darker purplish-red throat. The outside of the corolla tube is densely hairy. The globose, pea-sized fruit are shiny brown and papery at maturity, with the calyx lobes persistent at the distal end. Each capsule contains two black seeds, which are often dotted with white, needle-shaped crystals. In Florida, skunkvine usually flowers between May and September, and the fruit may persist on the vine through the winter months.
Skunkvine is native to temperate and tropical Asia. It has escaped cultivation and naturalized in North America, South America, the Mascarene Islands and the Pacific Islands. In the United States, it occurs in Hawaii, Texas, Louisiana, Florida, Georgia and the Carolinas.
Skunkvine has been vouchered from Florida counties scattered from Escambia in the north to Broward in the south. It is frequently found on disturbed sites such as residential landscapes, parks, abandoned lots, pastures, fencerows, roadsides and utility corridors. It also invades various native plant communities, including sandhills, floodplains, hammocks and upland mixed forests. Tolerant of varying soil and light conditions, from shady mesic hammocks to sunny xeric sandhills, it has even been observed growing in standing water.
Paederia cruddasiana, commonly known as sewervine, is easiest to distinguish from P. foetida when in fruit. The fruit of P. cruddasiana are ellipsoid to ovoid and laterally compressed, with conspicuous wings on the seed margins, while those of P. foetida are subglobose with unwinged seeds. In Florida, sewervine has been found only in Broward and Miami-Dade counties.
In its native habitat, skunkvine seeds are dispersed by birds. Although direct evidence is lacking, animal dispersal is suspected in its introduced range. Stems that are in contact with the soil readily develop adventitious roots at the nodes, and each stem fragment with a node is capable of developing into a new plant. Rooted stem fragments may be transported by construction machinery, in fill dirt and in nursery stock. Skunkvine is also cultivated as an ornamental and can escape from cultivation.
This species was introduced to the USDA Field Station at Brooksville, Florida, as a potential fiber crop in the late 19th century. By 1916, it was reported as a troublesome weed around the field station. Paederia cruddasiana was probably introduced at the same time, but was much more recently identified correctly as a separate species.
Skunkvine is an aggressive, fast-growing vine that can climb high up in trees or trail over the ground. It forms thick, tangled masses of vegetation, which may cover several acres, smothering understory plants and damaging or killing trees. It outcompetes and displaces native vegetation and disrupts natural forest succession.