Common name:Blue-leaf cactus
Scientific name:Opuntia robusta
Alternative common names:
Silver dollar, silver dollar cactus, silver dollar prickly pear, sweet purple cactus, wheel cactus, wheel pear.
Blue-leaf cactus is an upright and succulent shrub growing 1-4 m tall with much-branched stems consisting of a series of flattened fleshy segments. It most commonly infests pastures, granite outcrops and open woodlands.
Where does this species come from?Mexico
What is its invasive status in South Africa?NEMBA Category 1a Spineless cultivars and selections are not listed
Where in South Africa is it a problem?North West, Free State and Northern Cape Provinces
How does it spread?This species reproduces by stem fragments (i.e. stem segments easily become dislodged and produce roots) and also by seeds. Stem fragments are spread by becoming attached to animals, footwear and vehicles and are also dispersed in dumped garden waste. The fruit are eaten by various animals (e.g. birds and foxes) and the seeds spread in their droppings.
Why is it a problem?It’s regarded as an environmental weed.
What does it look like?Leaves:- No leaves. Flowers: - The large flowers (5-8 cm across) are yellow and occasionally have reddish-coloured streaks on the outer 'petals' (separate male and female flowers are often produced). Flowering occurs mostly during late spring and summer. Fruit/seeds: - Immature fruit are green in colour, but they turn pinkish to purplish in colour as they mature. These large fruit (7-8 cm long and about 6 cm wide) are fleshy, barrel-shaped or rounded (i.e. globose), and have several tufts of tiny barbed bristles on their surface. The dark red coloured pulp in the centre of the fleshy fruit contains large numbers of seeds (3-5 mm across). These seeds are generally light or dark brown in colour and rounded in shape.