Quick Facts

Quick facts

  • Spiked Pepper (Piper aduncum) is multi-stemmed shrub or small tree with aromatic leaves and twigs.
  • It is known to be naturalised on Christmas Island.
  • Currently it is not known to exist on the Australian continent, but has the potential to become a serious pest in the warm moist tropical regions.
  • It is an aggressive coloniser of disturbed habitats and natural open areas.
  • Is capable of forming dense thickets excluding other vegetation.

What Does It Look Like?

What is it?

Spiked Pepper (Piper aduncum) is a multi-stemmed shrub or small tree ranging in height from 1–7 m. It occasionally has prop roots supporting the lower trunk. The leaves and twigs emit an aromatic odour when crushed. The bark is smooth and grey to green in colour. The stems and branches are erect and have swollen purplish nodes. The leaves are arranged alternately in two rows on opposite sides of the branchlets. The leaf blades are elliptic to lance-shaped, measuring 12–22 cm long by 4–8 cm wide and attached to the stem by a stalk 2–7 mm long. The upper leaf surface is green and rough to the touch while the lower surface is pale green with a covering of short soft hairs. The leaf tip gradually tapers to a point and the leaf base is more or less rounded but asymmetrical.

The minute, white to pale yellow flowers are arranged in spirals on spikes measuring 10–12 cm long. The flowering spikes are borne singular on the branchlets opposite to where the leaves are attached, and are more or less erect, but arch over and droop towards the tip.

The fruiting spikes contain numerous berries embedded into the spike. Each berry contains a single seed and is green turning black in colour when ripe. The seeds are brown to black in colour with a surface of net-like veins and measure 0.7–1.25 mm long (Du Puy 1993; Waterhouse & Mitchell 1998; Jordan 2007)

For further information and assistance with identification of Spiked Pepper contact the Herbarium in your state or territory.

Flower colour

Yellow, White

Growth form (weed type/habit)

Tree, Shrub

Where it currently grows? Preferred habitat

Spiked Pepper is an aggressive coloniser of disturbed habitat and natural open areas such as clearings, roadsides, tree-fall gaps, landslides, pastures and tree plantations (Francis 2003; Waterhouse & Mitchell 1998). Spiked Pepper can grow from sea level up to 1800 m altitude, in areas receiving 1500–4000 mm of annual rainfall (Francis 2003; Hartemink 2002). Spiked Pepper will grow on most soil types except those that are excessively well drained or saline. It prefers full sun, but can survive and grow slowly under a moderate overstorey. It requires at least partial exposure to direct sunlight to grow large and flower (Francis 2003).

Are there similar species?

There are seven native Piper species in Australia, all of which are vines except Piper umbellatum L. Spiked Pepper is similar to Piper umbellatum in that it is a shrub growing to 3 m in height. However, Piper umbellatum is easily distinguished in having large heart-shaped leaves on stalks up to 30 cm long (Spokes 2007), whereas Spiked Pepper has lance shaped leaves, on stalks 2–7 mm long.

Why Is It A Weed?

What are its impacts?

Agriculture: Although Spiked Pepper is currently not known to exist on the Australian continent, it has the potential to become a serious pest in the warm moist tropical regions of northern Australia (Waterhouse 2003; Jordan 2007). Spiked Pepper can invade agricultural land and natural landscapes forming dense thickets that exclude other vegetation (AQIS 2005; Jordan 2007).

How does it spread?

Spiked Pepper is mostly spread by seed. The small single seeded berries are attractive to birds, fruit bats and other animals, which aid in dispersing the seeds. Spiked Pepper is also dispersed by wind and as contaminants on machinery. Spiked Pepper can spread short distances by suckering from the rootstock, forming large dense clumps (Waterhouse & Mitchell 1998; Hartemink 2001; AQIS 2005).

What is its history in Australia?

Spiked Pepper was introduced to Christmas Island either as a garden ornamental plant, or accidentally introduced on machinery or materials (Du Puy 1993; Swarbrick 1997 in PIER 2008).

How To Manage It?

Best practice management

Non-chemical control: Small plants of Spiked Pepper can be controlled manually by hand pulling or digging (Francis 2003). It is important to remove the entire plant, as Spiked Pepper can regenerate from the rootstock and stem fragments.

Chemical control: Larger plants can be treated by foliar spraying or the basal bark application of an appropriate herbicides. Plants can also be treated with a cut stump application of an appropriate herbicide (Langeland & Stocker 2000).

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au 

Does it have a biological control agent?


When does it grow? (lifecycle/growth calendar)

Spiked Pepper is a fast-growing shrub. It has the ability to sucker, and resprout from broken roots and stem fragments (cuttings) (Bourke 1997; Francis 2003). Spiked Pepper flowers and fruits throughout the year (Jordan 2007).

Where Is It Found?

Which states and territories is it found?

Found on Christmas Island but not on the Australian mainland.

What areas within states and territories is it found?

Spiked Pepper has not been recorded on the Australian continent, but is known to be naturalised on Christmas Island (Du Puy 1993). It has the potential to become a serious pest in the warm moist tropical regions of northern Australia (Waterhouse 2003; Jordan 2007).

Where does it originate?

Spiked Pepper is a native of tropical South and North America and the Caribbean Islands (Thorp & Wilson 2008).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?


Where is it a declared weed?


Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?


Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?


Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Piper aduncum

Other scientific names (synonyms)?


Does it have other known common name(s)?

Stilt Root Piper, Matico, False Kava, False Matico, Bamboo Piper, Jointwood, Cow's Foot, Higuillo De Hoja Menuda, Yaqona Ni Onolulu

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