Piper aduncum is a shrub or small tree up to 7m tall and 10cm or more in stem diameter, with short silt roots and medium-hard, brittle wood; foliage and twigs aromatic. Can grow as individual plants or in thickets. Branches are erect, but with drooping twigs and swollen, purplish nodes. Leaves alternate, distichous, elliptic, 12-22cm long, shortly petiolate; lamina scabrid above, with sunken nerves, softly hairy beneath. Inflorescence a leaf-opposed, curved spike on a 12-17cm peduncle, white to pale yellow, turning green with maturity. Flowers crowded in regular transverse ranks. Perianth absent; usually 4 stamens. Fruit a 1-seeded berry, compressed into greyish, wormlike spikes. Seeds brown to black, 0.7 -1.25mm long, compressed, with a reticulate surface (Waterhouse and Mitchell, 1998 in PIER, 2003).

In Fiji the red-vented bulbul (Pycnotus cafer), an introduced bird, is the chief disperser of P. aduncum seeds (Metcalfe, 1995).

Sprouts and suckers are able to grow more than a metre in their first year. Individual stems can live from 2 to several years, but through sprouting they can live for much longer (Francis, 2003).

Provides food and cover for wildlife, can be used for revegetating disturbed areas, and contributes to the biomass of forests (Francis, 2003). P. aduncum stakes are used in Papua New Guinea to create terraces for agriculture and to prevent erosion (Bourke, 1997).
Wood can be used for basic construction, fuel, stakes and fences. Has ornamental value and the fruit is used to season food. Essential oils from this species have antibacterial properties and may also be used as an insecticide and a molluscicide. Tea made from the leaves and roots is used to treat diarrhea, dysentery, vomiting, ulcers, and can also be used for the control of bleeding (Francis, 2003).

Disturbed rainforest areas and rainforest margins. Can grow up to 1700m in altitude (Bourke, 1997). In the Highlands of PNG this species goes up to 2000\r\nm (Pers. comm., Dr. Jan Leps) . In Fiji, it is an aggressive weed from sea level to 400m, most often along roadsides and in thickets, but also sometimes in secondary forest or on forested ridges, rarely found in intact rainforests (Smith, 1981 in PIER, 2003).
Lives in areas that receive from 1500 to greater than 4000mm of mean annual rainfall. Colonizes most soil types, apart from excessively well-drained soils, where it only grows at the upper end of the rainfall range; dry soils; and salty soils (Francis, 2003).
Requires high light levels and a bare soil surface, which means that disturbance is necessary for this species to establish. Moderately intolerant of shade, as it requires at least partial exposure to sunlight for it to reach a large size and flower (Francis, 2003).

Seeds can be dispersed by birds and a number of species of bat (PIER, 2003; Lobova and Mori, 2002). May be introduced into new areas on machinery, particularly logging equipment. Locally, it spreads by suckers, forming large clumps (PIER, 2003).

Propagation of this species can be carried out by planting cuttings directly into soil (Bourke, 1997). Piper aduncum flowers and fruits year-round. Seeds have a low germination rate, while cuttings are more successful (Francis, 2003). The seed weight reported is 0.17 mg (Leps et al. 2002). Also Garcia et al. reported that P. aduncum was the most common in viable seeds in faeces of bats.

Thought to have been introduced to Fiji in packing materials at Suva port (Plant Protection Service, 2001).Used for making agricultural terraces (Bourke, 1997).Used for agroforestry (Bourke, 1997).Widely planted as an ornamental tree (Francis, 2003).Movement of equipment has allowed this species to spread between land masses (Francis, 2003).

A pest in the Pacific, where it can become mixed with the kava (Piper methysticum) crop during harvesting, lowering its quality. Also competes with kava and other crops. May act as a host for kava pests and pathogens (Plant Protection Service, 2001).

Preventative measures: A Risk Assessment of Piper aduncum for Hawai‘i and other Pacific islands was \r\r\nprepared by Dr. Curtis Daehler (UH Botany) with funding from the Kaulunani \r\r\nUrban Forestry Program and US Forest Service. The alien plant screening system \r\r\nis derived from Pheloung et al. (1999) with minor modifications for use \r\r\nin Pacific islands (Daehler et al. 2004). The result is a score of 18 \r\r\nand a recommendation of: \"Likely to cause significant ecological or economic \r\r\nharm in Hawai‘i and on other Pacific Islands as determined by a high WRA score, \r\r\nwhich is based on published sources describing species biology and behaviour in \r\r\nHawai‘i and/or other parts of the world.\"

\r\nPhysical: Young plants can be uprooted by hand, although care must be \r\r\ntaken to ensure that no pieces of rhizome are left behind in the soil (UF/IFAS, \r\r\n2000).

Chemical: Basal bark application of 20% Garlon 4, or cut stems \r\r\nat ground level and apply 50% Garlon 3A to the stump (UF/IFAS, 2000).