Syngonium podophyllum
(arrowhead vine)

S. podophyllum is a fast-growing vine listed as an environmental and agricultural weed in the Global Compendium of Weeds (Randall, 2012). It is becoming highly invasive in tropical and subtropical areas where it climbs from the forest floor into the forest canopy engulfing mature trees and shading-out native vegetation in the understory (Queensland Department of Agriculture, Fisheries and Forestry, 2011; ISSG, 2012). S. podophyllum has established invasive populations in the United States (Florida and Hawaii), South Africa, Singapore, the West Indies (Cuba and Puerto Rico), and on several Pacific islands including American Samoa and Niue where infestations are having dramatic impacts on natural habitats (Space and Flynn, 2000; ISSG, 2012; PIER, 2012). In Florida, this species is listed as an invasive category I, considered to be altering native plant communities by displacing native species, changing community structures and ecological functions (Florida Exotic Pest Plant Council, 2011). S. podophyllum is listed as a weed in Australia and it is quickly becoming more common and widespread in areas of Queensland and Western Australia (Queensland Department of Agriculture, Fisheries and Forestry, 2011).

S. podophyllum is native to Mexico, Central America and parts of South America. The species has been widely introduced as an ornamental in tropical and subtropical regions and currently it can be found in the United States (Florida and Hawaii), South Africa, Australia, Singapore, Malaysia, China, the West Indies, and on several islands in the Pacific (Govaerts, 2012; ISSG, 2012; PIER, 2012; USDA-ARS, 2013).

The risk of introduction of S. podophyllum is high. It is a fast growing vine that is widely planted as an ornamental in tropical and subtropical regions (ISSG, 2012; PIER, 2012). Even when it has been demonstrated that this species has the potential to become invasive (Possley, 2004; Florida Exotic Pest Plant Council, 2011), it is still sold in the nursery and landscape trade around the world. Chong et al. (2010) strongly recommended in Singapore that growers should stop using the species as an ornamental plant due to its production of viable seeds and spontaneous spread.

S. podophyllum seems to be adapted to environmental conditions in both disturbed and undisturbed forests. It has escaped from gardens and cultivated areas and can now be found growing in shrublands, forest margins, disturbed sites, urban areas, abandoned land, agricultural land, wetlands, and roadsides in tropical and subtropical moist climates (Acevedo-Rodríguez, 2005; Chong et al., 2010; ISSG, 2012). The native habitat is in moist tropical forests of Central America (Chong et al., 2010).

In Florida, S. podophyllum is invading habitats that are the home of two endangered fern species: Asplenium verecundum and Tectaria fimbriata (Possley, 2004). In Costa Rica, this species has been reported as a weed in banana plantations (Garita, 2003).

Genetics

The chromosome number in S. podophyllum is 2n = 24 (Guha and Bhattacharya, 1987). 

Reproductive Biology

Although no pollinators have been reported in the literature for Syngonium species, Croat (1981) suggests that this genus may have the same type of pollination syndrome described for Philodendron, Dieffenbachia, and Xanthosoma, which are pollinated by large scarab beetles of the subfamilies Rutelinae and Dynastiniae.

Oppenheimer (2004) reported the discovery of a population in Hawaii that produced copious fruit, and the germination of 16 seedlings from 18 seeds collected from one of these fruits. 

Physiology and Phenology

In Puerto Rico, S. podophyllum has been collected in flower in February, July, and August, but there are no records of fruit production on this island (Acevedo-Rodríguez, 2005). In Australia, plants flower from January until late autumn, fruits mature during autumn-winter, seeds germinate in spring, and plants grow until summer (Queensland Department of Agriculture, Fisheries and Forestry, 2011). 

Environmental Requirements

S. podophyllum grows in moist and shady conditions in tropical climates. This species grows in sandy and loam soils with a pH ranging from 5.5 to 6. Within its native range in Central America it is most frequent in lowland moist forests but also occurs in premontane wet forest. It ranges in elevations from sea level to 1000 m but is more abundant below 750 m and especially abundant between 100 and 500 (Croat, 1982; Acevedo-Rodríguez, 2005; Queensland Department of Agriculture, Fisheries, and Forestry, 2011, ISSG, 2012; PIER, 2012).

Environmental

• Amenity

General

• Ornamental

Ornamental

• Potted plant
• Propagation material

Different sections of the genus Syngonium are distinguished based on leaf morphology. S. podophyllum belongs to section Syngonium, where adult leaf laminas are markedly divided but the pre-adult climbing phase has simple, hastate or sagittate leaves. In contrast, species of Sections Oblongatum and Cordatum have simple leaf laminas all through the phases from juvenile to adult, while the last section Pinnatilobum has lobed leaf laminas for both the pre-adult climbing and the adult phases (Chong et al., 2010). Within the section Syngonium, S. podophyllum differs from Syngonium auritum by its ellipsoid spathe tube and ovoid fruiting spadix, while S. auritum has a longer, cylindroid spathe tube and an elongate or cylindroid fruiting spadix.

Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Mechanical Control

Small infestations of S. podophyllum can be removed by hand pulling. Gloves should be worn when removing because the sap can be irritating to sensitive individuals. All plant segments must be removed from treated areas to achieve eradication because it may re-sprout from small root and plant fragments. Eradication of large infestations requires the use of special machinery (Space and Flynn, 2000; Queensland Department of Agriculture, Fisheries and Forestry, 2011; ISSG, 2012; PIER, 2012).   

Chemical Control

Specific research on the use of herbicides to control S. podophyllum has not been undertaken to date (Queensland Department of Agriculture, Fisheries and Forestry, 2011). For Queensland, use of the following herbicides is suggested based on registered controls for similar weeds:

• glyphosate: 1 L/100 L water
• triclopyr: 4 ml/1L water
• 2,4-D: 4 ml/1 L water
• fluroxypyr: 500 ml /100 L water
• metsulfuron-methyl: 10g/100 L water

Follow-up treatments are recommended until control is completed (Queensland Department of Agriculture and Fisheries, 2011; PIER, 2012).

12/07/13 Original text by:

Julissa Rojas-Sandoval, Department of Botany-Smithsonian NMNH, Washington DC, USA

Pedro Acevedo-Rodríguez, Department of Botany-Smithsonian NMNH, Washington DC, USA