Quick Facts

Quick facts

  • Sword Pear (Acanthocereus tetragonus) reproduces from fragments of stem and the succulent fruits are eaten by birds and animals who distribute the seed.
  • Once established, plants are drought tolerant.
  • It has the potential, like Harrisia cactus, to spread and reduce productivity of land.
  • Plants are spiny and can cause injury to humans and animals.
  • If this species is seen please notify your local weed management authority.

What Does It Look Like?

What is it?

Sword Pear (Acanthocereus tetragonus) is a shrub cactus with erect or clambering stems 1–5 m long, often arching and rooting at tips. The stems are 3–8 cm in diameter, prominently 3-angled (occasionally 4–5-angled) with coarsely wavy margins. The areoles (spots on stem segments and fruits that contain the spines) each have 4–7 (rarely 12) radial spines 1–5 cm long and 1 or 2 longer central spines.

The trumpet-like white flowers are nocturnal, 15–25 cm long, 8–10 cm diameter and located towards the branch tips.

The red fruit are 3–8 cm long, 2.5–7 cm diameter, naked or spiny and break irregularly from the top downwards. Seeds are numerous, black, smooth and shiny (Stanley & Ross 1983; Telford 1984; Anderson 2001; Pinkava 2003).

Flower colour


Growth form (weed type/habit)


Where it currently grows? Preferred habitat

Sword Pear occurs in disturbed Brigalow (Acacia harpophylla) forests on clays and is also recorded from near Rockhampton on river flats in forest growing on sandy soil (Telford 1984).

Are there similar species?

Harrisia cactus has a similar form to Sword Pear but differs in having 4–6-angled stems with 1 to several long spines and a number of smaller radial ones. Night-blooming cactus or moonlight cactus (Hylocereus undatus) differs in having areoles with 1 to 4 small spines 2–4 mm long and large fruits 10–12 cm in diameter bearing large fleshy scales. Tiger Pear (Opuntia aurantiaca) is easily distinguished by its very short rounded (terete) or subterete, detachable, stem segments rarely more than 20 cm long and the small yellow flowers (Chinnock 2007, pers. comm.).

Why Is It A Weed?

What are its impacts?

Native ecosystems: The succulent fruits of Sword Pear are eaten by birds and animals and the seed distributed in their droppings assisting its spread. Like Harrisia cactus this species has the potential to spread and cover large areas of land, impacting on the environment and reduce productivity.

Human and animal impact: The sharp spines are a hazard to both humans and animals (Chinnock 2007, pers. comm.).

How does it spread?

Sword Pear reproduces by seed and also by fragments of the fleshy (succulent) stem segments. Dispersal of seeds is primarily by birds or animals that eat the fruit. Small stem fragments may also be spread by animals or as discarded garden waste (Chinnock 2007, pers. comm.).

What is its history in Australia?

The exact date and means of introduction to Australia is unknown. The first known collection of Sword Pear is from Springsure, Queensland in 1926 (Hosking et al. 1988).

How To Manage It?

Best practice management

Chemical control: A registered herbicide can be undertaken.

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

Non-chemical control: Physical control: Small infestations and single plants should be cut off at or below ground level (Kleinschmidt & Johnson 1977).

Biological control: Sword Pear has also been recognised as a target for biological control through a cross-jurisdictional government process. This allows activities to be undertaken to develop effective biological controls. The Mealybug (Hypogeococcus festerianus) introduced for the biological control of Harrisia cactus (Harrisia martinii) occurs at Gogango and provides reasonable control of Sword Pear (Hosking et al. 1988)




Does it have a biological control agent?


When does it grow? (lifecycle/growth calendar)

Little information is available on the life cycle of Sword Pear. However, it is likely to be similar to Harrisia species (Chinnock 2007, pers. comm.).

Harrisia plants are active throughout most of the year in warmer areas. Flowering occurs mostly during spring and early summer, but may continue through until early autumn depending on conditions. The scented flowers open and night and collapse the following morning. Plants can start producing seed at age 6 months and from that age they can continue to produce fruit throughout the year. Seeds germinate after the first heavy rains of summer but the seedlings are fragile and easily destroyed by drought, trampling, grazing and cultivation (Parsons & Cuthbertson 2001; Navie 2004; Tanner 2007)

Where Is It Found?

Which states and territories is it found?


What areas within states and territories is it found?

Sword Pear occurs in wooded country over a large area north and south of Gogango in central Queensland. There are several small patches between Charters Towers and Jandowae (Hosking et al. 1988; AVH 2007).

Where does it originate?

Sword Pear extends from Florida through the Caribbean and Mexico south through Central America to northern South America in its native range (Anderson 2001).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?


Where is it a declared weed?

Not declared in any Australian state or territory

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

Acanthocereus tetragonus

Other scientific names (synonyms)?

Acanthocereus pentagonus (L.) Britton & Rose

Cactus pentagonus L.

Cereus pentagonus (L.) Haw.

Does it have other known common name(s)?

Barbed-wire Cactus, Triangle Cactus

Blackberry – a community-driven approach in Victoria

Blackberry the weed (Rubus fruticosus aggregate) was first introduced to Australia by European settlers in the mid-1800s as a fruit. It was recognised as a weed by mid-1880s. Blackberry is a serious issue across Australia. It is estimated that blackberry infests approximately 8.8 million hectares of land at an estimated cost of $103 million in annual control and production losses.

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