Westwood pear

Opuntia streptacantha
Succulent
Basal
Cladode
Yellow
Green
Discoloured

An upright or spreading fleshy shrub usually growing 50-100 cm tall. Its stems are much-branched and consist of a series of flattened, fleshy segments. These segments are (10-35 cm long, 7-20 cm wide, and 10-20 mm thick) and have groups of one of two sharp spines (2-4 cm long). The flowers (up to 7 cm long and 6-8 cm across) are bright yellow and are borne along the margins of the stem segments. The fleshy fruit turn reddish-purple in colour as they mature. Its fruit (4-8 cm long and 2.5-4 cm wide) are fleshy, egg-shaped, and usually have several tufts of small barbed bristles on their surface.

Common names 
Also known as: Nopal Cardón,
Family 
Cactaceae
Deciduous 
No
Flowering time 
Spring
Native/Exotic 
Exotic
Origin 
Mexico
Notifiable 
No
State declaration 
Category 3 - Must not be distributed or disposed. This means it must not be released into the environment unless the distribution or disposal is authorised in a regulation or under a permit.
Council declaration 
As per State Declaration
Known distribution 

Widely and densely dispersed along the Eastern parts of Australia.

Habitat 

Found in Semi-arid, sub-tropical, tropical and warmer temperate regions such as woodlands, grasslands, waterways, disturbed sites and coastal environments.

Habit 

An upright or spreading shrub usually growing 50-100 cm tall, but occasionally reaching up to 2 m in height.

Impact and control methods 

Westwood pear is regarded as an environmental weed in Queensland, New South Wales, Victoria and Western Australia. This species was recently listed as a priority environmental weed in two Natural Resource Management regions. It is also listed in the Global Invasive Species Database, and regarded to be in the top 100 of the world’s worst invasive alien species.

Stem and leaves 

The stems are much-branched and consist of a series of flattened, fleshy segments. These segments (10-35 cm long, 7-20 cm wide, and 10-20 mm thick) are green or bluish-green in colour and longer than they are broad. They are hairless and covered in small raised structures, which bear tiny spiny bristles These structures) either do not have any spines or may have one or two long sharp spines (2-4 cm long). The leaves are reduced to tiny cylindrical or cone-shaped structures (4.5-6 mm long) and are quickly shed from the developing stem segments.

Flowers and fruits 

The flowers (up to 7 cm long and 6-8 cm across) are bright yellow, but often have pinkish or reddish coloured markings on the outer 'petals'. They are borne singly on fleshy bases along the margins of the stem segments. Each flower has large numbers of 'petals' (most of these are actually petal-like structures known as petaloids) and numerous stamens. Flowering occurs mostly during spring and summer. The immature fruit are green in colour, but they turn reddish-purple as they mature. These berries (4-8 cm long and 2.5-4 cm wide) are fleshy (i.e. succulent), egg-shaped (i.e. obovoid), and usually have slightly depressed tips. Each fruit has several tufts of small barbed bristles (i.e. glochids) on its surface. The reddish or purplish coloured pulp in the centre of the fruit contains large numbers of seeds. These seeds (4-5 mm long and 4-4.5 mm wide) are generally yellow or pale brown in colour and somewhat rounded (i.e. sub-globular) in shape.

Reproduction and dispersal 

This plant reproduces by seed and also vegetatively via its fleshy (i.e. succulent) stem fragments. Stem fragments are spread by becoming attached to animals, footwear and vehicles. They may also be dispersed by floodwaters and in dumped garden waste. The fruits are eaten by various animals (e.g. birds and foxes) and the seeds then spread in their droppings.

Similar species 

Common prickly pear (Opuntia stricta) is very similar to spiny pest pear (Opuntia dillenii) and intermediates between the two species are sometimes seen in Australia.

It is also similar to Indian fig (Opuntia ficus-indica), white-spined prickly pear (Opuntia streptacantha), drooping tree pear (Opuntia monacantha) and velvety tree pear (Opuntia tomentosa).
These species can be distinguished by the following differences: common prickly pear (Opuntia stricta) is a low-growing plant (usually 50-100 cm tall) with relatively large flattened and elongated (i.e. elliptic or obovate) stem segments. These stem segments are hairless and generally do not have any spines (sometimes one or two large spines are present) on the small raised bumps (i.e. areoles) on their surfaces. The flowers are bright yellow and the fruit reddish-purple.spiny pest pear (Opuntia dillenii) is a low-growing plant (usually 50-100 cm tall) with relatively large flattened and elongated (i.e. elliptic or obovate) stem segments.
These stem segments are hairless and have groups of 1-7 large spines on most of the small raised bumps (i.e. areoles) on their surfaces. The flowers are bright yellow and the fruit reddish-purple.Indian fig (Opuntia ficus-indica) is a relatively tall shrubby or tree-like plant (usually 1.5-3 m tall) with very large flattened and elongated (i.e. oblong, elliptic or obovate) stem segments.
These stem segments are hairless and do not have any spines on the small raised bumps (i.e. areoles) on their surfaces. It has yellow flowers and reddish coloured fruit.white-spined prickly pear (Opuntia streptacantha) is a relatively tall and sometimes tree-like plant (usually 2-4 m tall) with flattened and egg-shaped (i.e. obovate) to almost circular (i.e. orbicular) stem segments.
These stem segments are hairless and have groups of 3-20 small white spines on most of the small raised bumps (i.e. areoles) on their surfaces. It has yellow flowers and dull red or yellowish coloured